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.
Thursday, July 03, 2008
S’pore Hokkien Huay Kuan 2007 PSLE Math Prelim Q42
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5 comments:
There is a simplier method to solve this question using Units Transfer Method. The concept involves is Before and After-Difference unchanged!
Please share your solution
What is Units Transfer Method.Is it in the Maths syllabus?
i read it in this book called unit transfer method in solving challenging maths problem. I bought it in this website: www.mathsheuristics.com
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
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