PSLE
Mr Chen used ³₈ of his money to buy 12 mangoes and 8 starfruits. The cost of 4 mangoes was the same as that of 2 starfruits. What was the most number of starfruits that Mr Chen could buy with the money he had left?
Fraction of his money that he had left
= 1 - ³₈ 
= ⁵₈

Let the cost of 1 mango be 1 M.
Let the cost of 1 starfruit be 1 S.

4 M = 2 S _(x3)
12 M = 6 S

Since Mr Chen wants to buy starfruits with the money he had left, 12 mangoes will be substituted as 6 starfruits.

³₈ of his money
= 12 M + 8 S
= 6 S + 8 S
= 14 S

³₈ of his money → 14 S
¹₈ of his money → ¹⁴₃ S
⁵₈ of his money → 5 x ¹⁴₃ S = 23¹₃ S

Maximum number of starfruits he could buy with the money that he had left = 23

Answer(s): 23