PSLE
Mr Soh used ²₅ of his money to buy 10 oranges and 3 persimmons. The cost of 5 oranges was the same as that of 3 persimmons. What was the most number of persimmons that Mr Soh could buy with the money he had left?
Fraction of his money that he had left
= 1 - ²₅ 
= ³₅

Let the cost of 1 orange be 1 O.
Let the cost of 1 persimmon be 1 P.

5 O = 3 P _(x2)
10 O = 6 P

Since Mr Soh wants to buy persimmons with the money he had left, 10 oranges will be substituted as 6 persimmons.

²₅ of his money
= 10 O + 3 P
= 6 P + 3 P
= 9 P

²₅ of his money → 9 P
¹₅ of his money → ⁹₂ P
³₅ of his money → 3 x ⁹₂ P = 13¹₂ P

Maximum number of persimmons he could buy with the money that he had left = 13

Answer(s): 13