PSLE
Mr Goh used ⁷₁₀ of his money to buy 9 mangosteens and 4 passion fruits. The cost of 3 mangosteens was the same as that of 4 passion fruits. What was the most number of passion fruits that Mr Goh could buy with the money he had left?
Fraction of his money that he had left
= 1 - ⁷₁₀ 
= ³₁₀

Let the cost of 1 mangosteen be 1 M.
Let the cost of 1 passion fruit be 1 P.

3 M = 4 P _(x3)
9 M = 12 P

Since Mr Goh wants to buy passion fruits with the money he had left, 9 mangosteens will be substituted as 12 passion fruits.

⁷₁₀ of his money
= 9 M + 4 P
= 12 P + 4 P
= 16 P

⁷₁₀ of his money → 16 P
¹₁₀ of his money → ¹⁶₇ P
³₁₀ of his money → 3 x ¹⁶₇ P = 6⁶₇ P

Maximum number of passion fruits he could buy with the money that he had left = 6

Answer(s): 6