PSLE
Mr Ma used ⁷₉ of his money to buy 12 pomegranates and 11 starfruits. The cost of 4 pomegranates was the same as that of 3 starfruits. What was the most number of starfruits that Mr Ma could buy with the money he had left?
Fraction of his money that he had left
= 1 - ⁷₉ 
= ²₉

Let the cost of 1 pomegranate be 1 P.
Let the cost of 1 starfruit be 1 S.

4 P = 3 S _(x3)
12 P = 9 S

Since Mr Ma wants to buy starfruits with the money he had left, 12 pomegranates will be substituted as 9 starfruits.

⁷₉ of his money
= 12 P + 11 S
= 9 S + 11 S
= 20 S

⁷₉ of his money → 20 S
¹₉ of his money → ²⁰₇ S
²₉ of his money → 2 x ²⁰₇ S = 5⁵₇ S

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

Answer(s): 5