PSLE
Vanessa and Tom bought pillows at the prices shown below.

3 Large pillows for $15
5 Small pillows for $12

1. Vanessa bought an equal number of large and small pillows. She spent $78 more on the large ones. How many pillows did she buy altogether?
2. Tom 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 Vanessa bought is the same. Make the number of large and small pillows the same. LCM of 3 and 5 is 15.

Cost of 3 large pillows = $15
Cost of 15 large pillows = 5 x 15 = $75

Cost of 5 small pillows = $12
Cost of 15 small pillows = 3 x 12 = $36

Difference in the cost of buying 15 small pillows and 15 large pillows
= 75 - 36
= $39

Number of sets of pillows
= 78 ÷ 39
= 2

Number of pillows that Vanessa bought
= 2 x 2 x 15
= 60

(b)
Tom 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 15 and 12 is 60.

Number of large pillows that Tom bought
= 3 x (60 ÷ 15)
= 3 x 4
= 12

Number of the small pillows that Tom bought
= 5 x (60 ÷ 12)
= 5 x 5
= 25

Fraction of the pillows that Tom bought that were large
= ¹²_{12 + 25}
= ¹²₃₇

Answer(s): (a) 60; (b) ¹²₃₇