PSLE
Zara and Brandon bought mangoes at the prices shown below.

2 Large mangoes for $7
5 Small mangoes for $4

1. Zara bought an equal number of large and small mangoes. She spent $54 more on the large ones. How many mangoes did she buy altogether?
2. Brandon spent an equal amount of money on the large and small mangoes. What fraction of the mangoes he bought were large?

(a)
Number of large and small mangoes that Zara bought is the same. Make the number of large and small mangoes the same. LCM of 2 and 5 is 10.

Cost of 2 large mangoes = $7
Cost of 10 large mangoes = 5 x 7 = $35

Cost of 5 small mangoes = $4
Cost of 10 small mangoes = 2 x 4 = $8

Difference in the cost of buying 10 small mangoes and 10 large mangoes
= 35 - 8
= $27

Number of sets of mangoes
= 54 ÷ 27
= 2

Number of mangoes that Zara bought
= 2 x 2 x 10
= 40

(b)
Brandon spent an equal amount of money on the large and small mangoes.  Make the amount of money spent on the large and small mangoes the same.
LCM of 7 and 4 is 28.

Number of large mangoes that Brandon bought
= 2 x (28 ÷ 7)
= 2 x 4
= 8

Number of the small mangoes that Brandon bought
= 5 x (28 ÷ 4)
= 5 x 7
= 35

Fraction of the mangoes that Brandon bought that were large
= ⁸_{8 + 35}
= ⁸₄₃

Answer(s): (a) 40; (b) ⁸₄₃