PSLE
Min baked a total of 21 large and small cakes in the ratio of 4 : 3. She decorated each cake with some blueberries in the ratio of 8 : 5. She used a total of 218 blueberries to decorate all the small cakes and 8 large cakes.

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

(a)
Fraction of the cakes that were large ones = ⁴_{4 + 3} = ⁴₇

Number of large cakes
= ⁴₇ x 21
= 12

Number of small cakes
= 21 - 12
= 9

	Large cakes	Small cakes	Total
Number	8	9
Value	8 u	5 u
Total value	64 u	45 u	109 u

(b)
Number of blueberries used to decorate 8 large cakes and 9 small cakes
= 64 u + 45 u
= 109 u

109 u = 218

1 u = 218 ÷ 109 = 2

Number of blueberries used to decorate all the small cakes
= 45 u
= 45 x 2
= 90

(c)
Number of blueberries to decorate one large cake
= 8 u
= 8 x 2
= 16

Number of remaining large cakes that were decorated yet
= 12 - 8
= 4

Number of more blueberries that Min needed to decorate the remaining large cakes
= 4 x 16
= 64

Answer(s): (a) 9; (b) 90; (c) 64