PSLE
Mr Song used ⁷₁₀ of his money to buy 6 passion fruits and 4 mangosteens. The cost of 2 passion fruits was the same as that of 4 mangosteens. What was the most number of mangosteens that Mr Song could buy with the money he had left?
Fraction of his money that he had left
= 1 - ⁷₁₀ 
= ³₁₀

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

2 P = 4 M _(x3)
6 P = 12 M

Since Mr Song wants to buy mangosteens with the money he had left, 6 passion fruits will be substituted as 12 mangosteens.

⁷₁₀ of his money
= 6 P + 4 M
= 12 M + 4 M
= 16 M

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

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

Answer(s): 6