PSLE
Mr Yap used ³₁₀ of his money to buy 15 apples and 11 passion fruits. The cost of 5 apples was the same as that of 4 passion fruits. What was the most number of passion fruits that Mr Yap could buy with the money he had left?
Fraction of his money that he had left
= 1 - ³₁₀ 
= ⁷₁₀

Let the cost of 1 apple be 1 A.
Let the cost of 1 passion fruit be 1 P.

5 A = 4 P _(x3)
15 A = 12 P

Since Mr Yap wants to buy passion fruits with the money he had left, 15 apples will be substituted as 12 passion fruits.

³₁₀ of his money
= 15 A + 11 P
= 12 P + 11 P
= 23 P

³₁₀ of his money → 23 P
¹₁₀ of his money → ²³₃ P
⁷₁₀ of his money → 7 x ²³₃ P = 53²₃ P

Maximum number of passion fruits he could buy with the money that he had left = 53

Answer(s): 53