Heuristic problems...pls help

amberz SG

Q1) A box contains both pink and blue pens. 1/2 of the pink pens and 1/3 of the blue pens make up a total of 13 pens. 1/3 of the pink pens and 1/2 of the blue pens make up a total of 12 pens. How many pens are there of each colour?

Q2) I have these coins... 5 cents, 10 cents, 20 cents, 50 cents and 1 dollar. What are the amounts I can make with three of these coins?

Q3) Mrs Ravi spent half of her money and $10 at the first shop. She spent half her remaining money and $10 at the second shop. She spent half of what was left of her money and $10 at the third shop.After that, she had no more money left. How much money did she have to begin with when she went to the first shop?

Q4) Mike and Peter have an equal number of coins in their piggy bank. Everyday, Mike takes out 3 coins and Peter takes out 1 coin.Sometime later, when Mike empties his piggy bank, Peter has 60 coins left. How many coins did they have altogether at first?

ThunderFbolt SG

1) got do algebra before?

1/2 p + 1/3 b = 13 and 1/3 p + 1/2 b = 12

Or 3p + 2b = 78 and 2p + 3b = 72

pink pens = 18, blue pens = 12.

2) ownself try lah... primary school when buying tit-bits sure got do this kind of calculation...

3) "She spent half of what was left of her money and $10 at the third shop.After that, she had no more money left. "

means that $10 was her third "half". just keep adding and work backwards from that. should be $140 (calculating off top of head).

4) if Peter has 60 coins left when Mike has none, this means that the 60 coins refer to the 2 extra coins Mike takes out each day. let the 2 extra coins be 2 units representing 60 coins. total should be... $180.