Author Topic: Arithmetic that makes you cringe  (Read 14454 times)

Re: Arithmetic that makes you cringe
« Reply #125 on: October 02, 2019, 01:41:43 pm »
No, you'd be putting 10 times too much on!

1ml = 10-6m3
1ha = 104m2
1ml/ha = 10-6/104m = 10-10m = 1 ångström

Mind you, my experience of applying agri-death is that it's nigh-impossible to spray anything like evenly.

Cudzoziemiec

  • Waking up now, put the kettle on!
Re: Arithmetic that makes you cringe
« Reply #126 on: October 02, 2019, 02:56:52 pm »
Financial analyst: What are the prospects for Product X?
Big boss: Product X sells £3.2 million, which is 8% of total sales. We have the capacity to increase that to 15%.
FA: Okay... my maths isn't that great.
BB: Alright, we can basically almost double it.
I do not ride a great big Mercian, gangster tanwalls, fixed cog in the back.

T42

  • Tea tank
Re: Arithmetic that makes you cringe
« Reply #127 on: October 02, 2019, 03:26:26 pm »
Wikipedia tells me CGS = centimetre, gram, second and MKS = metre, kilogram, second. To my mind these are the same system, just at different scales. Isn't half the point of metric/SI that it's easy to relate between different scales because everything goes up and down in 10s, rather than an assortment of 12s, 16s, 20s and whatever in Imperial (and various other pre-metric systems)?

The danger with metric-based systems is losing track of the decimal point.  I did this during my A-level physics practical and the invigilator, who was wandering round making sure nobody was using a crafty AVOmeter, glanced at my pad and murmured "you might want to check that" as he passed my bench.
I've dusted all those old bottles and set them up straight.

fuaran

  • rothair gasta
Re: Arithmetic that makes you cringe
« Reply #128 on: October 02, 2019, 03:49:58 pm »
Financial analyst: What are the prospects for Product X?
Big boss: Product X sells £3.2 million, which is 8% of total sales. We have the capacity to increase that to 15%.
FA: Okay... my maths isn't that great.
BB: Alright, we can basically almost double it.
Depends on whether the total sales stay the same, or increase, or decrease...

Re: Arithmetic that makes you cringe
« Reply #129 on: October 02, 2019, 03:57:10 pm »
The danger with metric-based systems is losing track of the decimal point.  I did this during my A-level physics practical and the invigilator, who was wandering round making sure nobody was using a crafty AVOmeter, glanced at my pad and murmured "you might want to check that" as he passed my bench.
Indeed.  We (structural engineers) measure on site to mm, but work out loads in kN/m2 or kN/m.  Steel section serial sizes are related to the dimension in mm, but the tables of section properties quote Z in cm3 and I in cm4 (zenzizenzic centimetres, FYI).  Yield strengths of steels are quoted in MPa (N/mm2 or 103kN/m2).  Young's modulus is quoted in GPa (kN/mm2).

Cudzoziemiec

  • Waking up now, put the kettle on!
Re: Arithmetic that makes you cringe
« Reply #130 on: October 02, 2019, 04:20:59 pm »
Financial analyst: What are the prospects for Product X?
Big boss: Product X sells £3.2 million, which is 8% of total sales. We have the capacity to increase that to 15%.
FA: Okay... my maths isn't that great.
BB: Alright, we can basically almost double it.
Depends on whether the total sales stay the same, or increase, or decrease...
Not really. The question was about capacity not potential sales. The FA simply had to realize that 15 is approximately double 8.
I do not ride a great big Mercian, gangster tanwalls, fixed cog in the back.

Cudzoziemiec

  • Waking up now, put the kettle on!
Re: Arithmetic that makes you cringe
« Reply #131 on: December 16, 2019, 11:49:49 am »
Quote
Across the Bristol area, roughly three in four people over the age of 18 voted in the General Election. Across the country, it was fewer than two in three.

Nationally, turnout in the 2019 election was 67.2 per cent - down 1.6 per cent on the poll in 2017.
I do not ride a great big Mercian, gangster tanwalls, fixed cog in the back.

Giraffe

  • I brake for Giraffes
Re: Arithmetic that makes you cringe
« Reply #132 on: December 17, 2019, 08:56:58 am »
Quote
Across the Bristol area, roughly three in four people over the age of 18 voted in the General Election. Across the country, it was fewer than two in three.

Nationally, turnout in the 2019 election was 67.2 per cent - down 1.6 per cent on the poll in 2017.
So, fewer means either one or none.
Also, the bit "roughly three in four people over the age of 18 voted" seems to be either redundant or leaves me wondering about the proportion of under-18 voters.
2x4: thick plank; 4x4: 2 of 'em.

Re: Arithmetic that makes you cringe
« Reply #133 on: December 18, 2019, 07:54:26 am »
Also, the bit "roughly three in four people over the age of 18 voted" seems to be either redundant or leaves me wondering about the proportion of under-18 voters.
Mr. Drumpf would say they were the Hillary voters.

Would it be clearer to say "roughly three in four people of voting age voted" ?

ElyDave

  • Royal and Ancient Polar Bear Society member 263583
Re: Arithmetic that makes you cringe
« Reply #134 on: December 18, 2019, 09:07:30 am »
surely the easiest way would be to say 2sq.m and 2m2 to avoid confusion?  Happens regularly in my industry - both the designations and confusion
“Procrastination is the thief of time, collar him.” –Charles Dickens

ian

  • fatuously disingenuous
    • The Suburban Survival Guide
Re: Arithmetic that makes you cringe
« Reply #135 on: December 18, 2019, 09:17:39 am »
Also, the bit "roughly three in four people over the age of 18 voted" seems to be either redundant or leaves me wondering about the proportion of under-18 voters.
Mr. Drumpf would say they were the Hillary voters.

Would it be clearer to say "roughly three in four people of voting age voted" ?

Why not just three quarters in Bristol compared with two-thirds across the country. When did fractions become so vulgar?
!nataS pihsroW

Cudzoziemiec

  • Waking up now, put the kettle on!
Re: Arithmetic that makes you cringe
« Reply #136 on: December 18, 2019, 09:27:54 am »
Quote
Across the Bristol area, roughly three in four people over the age of 18 voted in the General Election. Across the country, it was fewer than two in three.

Nationally, turnout in the 2019 election was 67.2 per cent - down 1.6 per cent on the poll in 2017.
So, fewer means either one or none.
Also, the bit "roughly three in four people over the age of 18 voted" seems to be either redundant or leaves me wondering about the proportion of under-18 voters.
Good point about fewer, but if that were the problem, it would be in the Grammar thread. All I noticed is that 67.2% is more than two in three.
I do not ride a great big Mercian, gangster tanwalls, fixed cog in the back.

Re: Arithmetic that makes you cringe
« Reply #137 on: January 16, 2020, 11:26:50 pm »
Quote
Kashmir covers around 86,000 sq miles (138 sq km), and is famed for the beauty of its lakes, meadows and snow-capped mountains.

From https://www.bbc.co.uk/news/world-asia-51131294
Rust never sleeps

Re: Arithmetic that makes you cringe
« Reply #138 on: January 16, 2020, 11:45:44 pm »
If you order something that's basically a closed flexible band, that's to go round something round, and it's described as having "diameter: 4cm".
When you get it, you lay it flat on a surface (so it's doubled up) and measure it. 4cm.
IS that it's diameter?? Cos to me, that's half the circumference.
It is what it is. It's not what it's not, so it must be what it is.

Cudzoziemiec

  • Waking up now, put the kettle on!
Re: Arithmetic that makes you cringe
« Reply #139 on: January 27, 2020, 09:39:45 am »
Monday puzzle in that there Grauniad:
Quote
Here’s another numerical palindrome:

50, 20, 10, 01, 02, 05

It’s the pence value of the UK coins in circulation under a pound.

What is the highest value of UK coins you can have in your pocket without being able to exchange them exactly for a £10 note?

(This puzzle is filed under. ‘Not difficult but you’d be surprised at how many people get it wrong.’)
I don't get this. How could the answer possibly not be £9.99? But there must be something else cos that's just too obvious. Does he mean only using each value of coin once? Or what? It feels like there's some assumption that's so obvious he hasn't stated it but I'm missing it.
I do not ride a great big Mercian, gangster tanwalls, fixed cog in the back.

nicknack

  • Hornblower
Re: Arithmetic that makes you cringe
« Reply #140 on: January 27, 2020, 10:17:11 am »
Monday puzzle in that there Grauniad:
Quote
Here’s another numerical palindrome:

50, 20, 10, 01, 02, 05

It’s the pence value of the UK coins in circulation under a pound.

What is the highest value of UK coins you can have in your pocket without being able to exchange them exactly for a £10 note?

(This puzzle is filed under. ‘Not difficult but you’d be surprised at how many people get it wrong.’)
I don't get this. How could the answer possibly not be £9.99? But there must be something else cos that's just too obvious. Does he mean only using each value of coin once? Or what? It feels like there's some assumption that's so obvious he hasn't stated it but I'm missing it.
Dunno what the actual answer is, but if you had a 19x50s and 3x20s then you'd have £10.10 which is more than £9.99.
<thinks>
Or 49x20s and 1x50 = £10.30
There's no vibrations, but wait.

Re: Arithmetic that makes you cringe
« Reply #141 on: January 27, 2020, 10:19:02 am »
My interpretation is

Quote
What is the highest value of UK coins you can have in your pocket without being able to exchange some of them exactly for a £10 note?

If you had 49no 20pences and 1no 50pence, you'd have £10.30, but wouldn't be able to make £10.  I think this is the solution.

See also: 43 Chicken McNuggets

Edit: cross-posted with nicknack!

Re: Arithmetic that makes you cringe
« Reply #142 on: January 27, 2020, 10:47:14 am »
You could also add 5p and 2 x 2p to that and still not be able to make up £10, so £10.39
If you don’t make time for exercise now, sooner or later you’ll need to make time for ill health.

Re: Arithmetic that makes you cringe
« Reply #143 on: January 27, 2020, 11:17:24 am »
Good spot!

Cudzoziemiec

  • Waking up now, put the kettle on!
Re: Arithmetic that makes you cringe
« Reply #144 on: January 27, 2020, 11:23:16 am »
My interpretation is

Quote
What is the highest value of UK coins you can have in your pocket without being able to exchange some of them exactly for a £10 note?

If you had 49no 20pences and 1no 50pence, you'd have £10.30, but wouldn't be able to make £10.  I think this is the solution.
Okay, that makes sense. And Nicknack's answer, which has the advantage of being almost palindromic.

Quote
See also: 43 Chicken McNuggets
What?  ???
I do not ride a great big Mercian, gangster tanwalls, fixed cog in the back.

Re: Arithmetic that makes you cringe
« Reply #145 on: January 27, 2020, 12:40:39 pm »
43 is the largest number of Chicken McNuggets which couldn't be made using the standard sized packs (6, 9, 20).

Cudzoziemiec

  • Waking up now, put the kettle on!
Re: Arithmetic that makes you cringe
« Reply #146 on: January 27, 2020, 02:15:21 pm »
43 is the largest number of Chicken McNuggets which couldn't be made using the standard sized packs (6, 9, 20).
This is why McDonalds have their own university!
I do not ride a great big Mercian, gangster tanwalls, fixed cog in the back.

Wowbagger

  • Dez's butler
    • Musings of a Gentleman Cyclist
Re: Arithmetic that makes you cringe
« Reply #147 on: January 27, 2020, 02:22:22 pm »
43 is the largest number of Chicken McNuggets which couldn't be made using the standard sized packs (6, 9, 20).

This reminds me of a rather neat problem I recall from my primary school teaching days.

A 40kg weight drops on the floor and breaks into 4 pieces. It so happens that the pieces are precisely the correct mass to allow any number of whole kilograms from 1 to 40 to be weighed on a balance. What is the mass of each of the 4 pieces?
Oh, Bach without any doubt. Bach every time for me.

rr

Re: Arithmetic that makes you cringe
« Reply #148 on: January 27, 2020, 04:15:40 pm »
You could also add 5p and 2 x 2p to that and still not be able to make up £10, so £10.39
Can't you have 4×2p, making £10.43?

Sent from my moto x4 using Tapatalk


rr

Re: Arithmetic that makes you cringe
« Reply #149 on: January 27, 2020, 05:27:08 pm »
You could also add 5p and 2 x 2p to that and still not be able to make up £10, so £10.39
Can't you have 4×2p, making £10.43?

Sent from my moto x4 using Tapatalk
Indeed you can, the answer is £10.43

Sent from my moto x4 using Tapatalk