PSLE
Mr Tang used ⁵₈ of his money to buy 10 mangoes and 3 starfruits. The cost of 5 mangoes was the same as that of 3 starfruits. What was the most number of starfruits that Mr Tang could buy with the money he had left?
Fraction of his money that he had left
= 1 - ⁵₈ 
= ³₈

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

5 M = 3 S _(x2)
10 M = 6 S

Since Mr Tang wants to buy starfruits with the money he had left, 10 mangoes will be substituted as 6 starfruits.

⁵₈ of his money
= 10 M + 3 S
= 6 S + 3 S
= 9 S

⁵₈ of his money → 9 S
¹₈ of his money → ⁹₅ S
³₈ of his money → 3 x ⁹₅ S = 5²₅ S

Maximum number of starfruits he could buy with the money that he had left = 5

Answer(s): 5