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.

Thursday, July 03, 2008

S’pore Hokkien Huay Kuan 2007 PSLE Math Prelim Q42

Mrs Lim bought a total of 120 apples and oranges in the ratio of 3 : 5. After she gave away an equal number of each type of fruit, the ratio of the number of apples to the number of oranges left is 3 : 8. How many apples does she have now?

Solution

Apples : Oranges ----- 3 : 5 (Total 120 fruits)

Hence, 8 units ----- 120
1 unit ----- 120 divided by 8 = 15

(Apples) 3 units ----- 15 x 3 = 45
(Oranges) 5 units ----- 15 x 5 = 75



5 units ----- 30
1 unit ----- 30 divided by 5 = 6
(Apples left) 3 units ----- 3 x 6 = 18

Answer: She has 18 apples left.

Note – “The Singapore Hokkien Huay Kuan 5-School Combined Prelim Maths” is the common Maths Prelim Exam for Tao Nan, Ai Tong, Chongfu, Nan Chiau and Kong Hwa schools.

5 comments:

Anonymous said...

There is a simplier method to solve this question using Units Transfer Method. The concept involves is Before and After-Difference unchanged!

Anonymous said...

Please share your solution

Anonymous said...

What is Units Transfer Method.Is it in the Maths syllabus?

Anonymous said...

i read it in this book called unit transfer method in solving challenging maths problem. I bought it in this website: www.mathsheuristics.com

Anonymous said...

Apples Oranges Difference

Before 3x5=15 5x5=25 2x5=10

Change -? -?

After 3x2=6 8x2=16 5x2=10

(15+25)u=120
1u = 120/40=3
6u = 6x3= 18