PSLE
Min and Asher bought pillows at the prices shown below.

3 Large pillows for $7
4 Small pillows for $5

1. Min bought an equal number of large and small pillows. She spent $52 more on the large ones. How many pillows did she buy altogether?
2. Asher spent an equal amount of money on the large and small pillows. What fraction of the pillows he bought were large?

(a)
Number of large and small pillows that Min bought is the same. Make the number of large and small pillows the same. LCM of 3 and 4 is 12.

Cost of 3 large pillows = $7
Cost of 12 large pillows = 4 x 7 = $28

Cost of 4 small pillows = $5
Cost of 12 small pillows = 3 x 5 = $15

Difference in the cost of buying 12 small pillows and 12 large pillows
= 28 - 15
= $13

Number of sets of pillows
= 52 ÷ 13
= 4

Number of pillows that Min bought
= 4 x 2 x 12
= 96

(b)
Asher spent an equal amount of money on the large and small pillows.  Make the amount of money spent on the large and small pillows the same.
LCM of 7 and 5 is 35.

Number of large pillows that Asher bought
= 3 x (35 ÷ 7)
= 3 x 5
= 15

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

Fraction of the pillows that Asher bought that were large
= ¹⁵_{15 + 28}
= ¹⁵₄₃

Answer(s): (a) 96; (b) ¹⁵₄₃