This blog is managed by Song Hock Chye, author of Improve Your Thinking Skills in Maths (P1-P3 series), which is published and distributed by EPH.

Tuesday, February 05, 2008

Tao Nan School P6 Math CA1 2004 (Q43)

Ravi and Ali shared a sum of money in the ratio of 4 : 7. After Ravi spent ¼ of his money, he had $32 less than Ali.
a) How much money had Ravi left?
b) Ali then spent ½ of his money. What is the new ratio of the amount of money Ravi has to the amount of money Ali has?


* Ravi spent ¼ of his money. ¼ of 4 units is 1 unit. Therefore after spending, Ravi would have 3 units left.

The difference between Ali and Ravi after Ravi spent ¼ of his money is

7 units (of Ali’s money) – 3 units (of Ravi’s money) = 4 units

4 units ---- $32 (Ravi had $32 less than Ali)

1 unit ----- $32 divided by 4 = $8


3 units ----- $8 x 3 = $24.

Answer: Ravi had $24 left.


Ali then spent half of his money. Since Ali had 7 units, half of that would mean 3 and a half units spent.

* Multiply by 2 to give a whole number for Ali’s ratio of 3½.

Answer: The Ratio of amount of money Ravi has to the amount of Ali has is 6 : 7.

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