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.

## Wednesday, September 07, 2011

### Hokkien Huay Kuan Combined Primary 2010 PSLE Math Prelim Paper 2 Q16

Yanling had 60% more stamps than Lena. Tricia had 75% fewer stamps than Yanling. Yanling and Lena gave Tricia some stamps in the ratio 4:1. As a result, Tricia had 2 and 1/2 times as many stamps as before and Yanling had 300 stamps more than Lena in the end. How many sttamps did Lena give to Tricia?

Solution

*** Tricia had 75% fewer stamps than Yanling
----- 25% of 160% is 40%.

# Tricia finally had 2 and half times as many stamps as before
----- 40% x 2.5 = 100%

Tricia's number of stamps increased by
---- 100% - 40% = 60%

Ratio given by Yanling and Lena was 4:1 -----
Y : L
4 : 1
(Total 5 units) ----- 60%

**(Lena gave) 1 unit ----- 60% divided by 5 = 12%
*(Yanling gave) 4 units ---- 4 x 12% = 48%

In the end, Yanling had more than Lena ----- 300
112% - 88% ----- 300
24% ---- 300
1% ---- 300 divided by 24 = 12.5

Lena gave Tricia 12% -----
12 x 12.5 = 150