PSLE
Vanessa and Ethan bought storybooks at the prices shown below.

3 Large storybooks for $10
4 Small storybooks for $6

1. Vanessa bought an equal number of large and small storybooks. She spent $88 more on the large ones. How many storybooks did she buy altogether?
2. Ethan spent an equal amount of money on the large and small storybooks. What fraction of the storybooks he bought were large?

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

Cost of 3 large storybooks = $10
Cost of 12 large storybooks = 4 x 10 = $40

Cost of 4 small storybooks = $6
Cost of 12 small storybooks = 3 x 6 = $18

Difference in the cost of buying 12 small storybooks and 12 large storybooks
= 40 - 18
= $22

Number of sets of storybooks
= 88 ÷ 22
= 4

Number of storybooks that Vanessa bought
= 4 x 2 x 12
= 96

(b)
Ethan spent an equal amount of money on the large and small storybooks.  Make the amount of money spent on the large and small storybooks the same.
LCM of 10 and 6 is 30.

Number of large storybooks that Ethan bought
= 3 x (30 ÷ 10)
= 3 x 3
= 9

Number of the small storybooks that Ethan bought
= 4 x (30 ÷ 6)
= 4 x 5
= 20

Fraction of the storybooks that Ethan bought that were large
= ⁹_{9 + 20}
= ⁹₂₉

Answer(s): (a) 96; (b) ⁹₂₉