PSLE
Kimberly baked a total of 27 large and small cakes in the ratio of 7 : 2. She decorated each cake with some raspberries in the ratio of 3 : 2. She used a total of 252 raspberries to decorate all the small cakes and 10 large cakes.

1. How many small cakes did Kimberly bake?
2. What was the number of raspberries used to decorate all the small cakes?
3. How many more raspberries did Kimberly need to decorate the remaining large cakes?

(a)
Fraction of the cakes that were large ones = ⁷_{7 + 2} = ⁷₉

Number of large cakes
= ⁷₉ x 27
= 21

Number of small cakes
= 27 - 21
= 6

	Large cakes	Small cakes	Total
Number	10	6
Value	3 u	2 u
Total value	30 u	12 u	42 u

(b)
Number of raspberries used to decorate 10 large cakes and 6 small cakes
= 30 u + 12 u
= 42 u

42 u = 252

1 u = 252 ÷ 42 = 6

Number of raspberries used to decorate all the small cakes
= 12 u
= 12 x 6
= 72

(c)
Number of raspberries to decorate one large cake
= 3 u
= 3 x 6
= 18

Number of remaining large cakes that were decorated yet
= 21 - 10
= 11

Number of more raspberries that Kimberly needed to decorate the remaining large cakes
= 11 x 18
= 198

Answer(s): (a) 6; (b) 72; (c) 198