You, sonny, work for a builders merchants. I am a clueless fecker who knows fuck all about such things, so when I ask how much sand and cement I need to lay 11 sq m of slabs, I do not expect to hear, & I quote: "I haven't got a clue, mate". I cannot be the first clueless fecker to have called you, so get a clue, dipstick. I realise it's a "how long's a piece of string" question, but help me narrow it down, why don't you?