PSLE
Marion and Riordan bought towels at the prices shown below.

4 Large towels for $15
7 Small towels for $10

1. Marion bought an equal number of large and small towels. She spent $260 more on the large ones. How many towels did she buy altogether?
2. Riordan spent an equal amount of money on the large and small towels. What fraction of the towels he bought were small?

(a)
Number of large and small towels that Marion bought is the same. Make the number of large and small towels the same. LCM of 4 and 7 is 28.

Cost of 4 large towels = $15
Cost of 28 large towels = 7 x 15 = $105

Cost of 7 small towels = $10
Cost of 28 small towels = 4 x 10 = $40

Difference in the cost of buying 28 small towels and 28 large towels
= 105 - 40
= $65

Number of sets of towels
= 260 ÷ 65
= 4

Number of towels that Marion bought
= 4 x 2 x 28
= 224

(b)
Riordan spent an equal amount of money on the large and small towels. Make the amount of money spent on the large and small towels the same.
LCM of 15 and 10 is 30.

Number of large towels that Riordan bought
= 4 x (30 ÷ 15)
= 4 x 2
= 8

Number of the small towels that Riordan bought
= 7 x (30 ÷ 10)
= 7 x 3
= 21

Fraction of the towels that Riordan bought that were small
= ²¹_{8 + 21}
= ²¹₂₉

Answer(s): (a) 224; (b) ²¹₂₉