PSLE
Rachel and David bought mangoes at the prices shown below.

2 Large mangoes for $6
3 Small mangoes for $4

1. Rachel bought an equal number of large and small mangoes. She spent $40 more on the large ones. How many mangoes did she buy altogether?
2. David 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 Rachel bought is the same. Make the number of large and small mangoes the same. LCM of 2 and 3 is 6.

Cost of 2 large mangoes = $6
Cost of 6 large mangoes = 3 x 6 = $18

Cost of 3 small mangoes = $4
Cost of 6 small mangoes = 2 x 4 = $8

Difference in the cost of buying 6 small mangoes and 6 large mangoes
= 18 - 8
= $10

Number of sets of mangoes
= 40 ÷ 10
= 4

Number of mangoes that Rachel bought
= 4 x 2 x 6
= 48

(b)
David 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 6 and 4 is 12.

Number of large mangoes that David bought
= 2 x (12 ÷ 6)
= 2 x 2
= 4

Number of the small mangoes that David bought
= 3 x (12 ÷ 4)
= 3 x 3
= 9

Fraction of the mangoes that David bought that were large
= ⁴_{4 + 9}
= ⁴₁₃

Answer(s): (a) 48; (b) ⁴₁₃