PSLE
Irene baked a total of 22 large and small cakes in the ratio of 8 : 3. She decorated each cake with some grapes in the ratio of 5 : 3. She used a total of 146 grapes to decorate all the small cakes and 11 large cakes.

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

(a)
Fraction of the cakes that were large ones = ⁸_{8 + 3} = ⁸₁₁

Number of large cakes
= ⁸₁₁ x 22
= 16

Number of small cakes
= 22 - 16
= 6

	Large cakes	Small cakes	Total
Number	11	6
Value	5 u	3 u
Total value	55 u	18 u	73 u

(b)
Number of grapes used to decorate 11 large cakes and 6 small cakes
= 55 u + 18 u
= 73 u

73 u = 146

1 u = 146 ÷ 73 = 2

Number of grapes used to decorate all the small cakes
= 18 u
= 18 x 2
= 36

(c)
Number of grapes to decorate one large cake
= 5 u
= 5 x 2
= 10

Number of remaining large cakes that were decorated yet
= 16 - 11
= 5

Number of more grapes that Irene needed to decorate the remaining large cakes
= 5 x 10
= 50

Answer(s): (a) 6; (b) 36; (c) 50