PSLE
Fiona baked a total of 20 large and small cakes in the ratio of 7 : 3. She decorated each cake with some strawberries in the ratio of 9 : 4. She used a total of 315 strawberries to decorate all the small cakes and 9 large cakes.

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

(a)
Fraction of the cakes that were large ones = ⁷_{7 + 3} = ⁷₁₀

Number of large cakes
= ⁷₁₀ x 20
= 14

Number of small cakes
= 20 - 14
= 6

	Large cakes	Small cakes	Total
Number	9	6
Value	9 u	4 u
Total value	81 u	24 u	105 u

(b)
Number of strawberries used to decorate 9 large cakes and 6 small cakes
= 81 u + 24 u
= 105 u

105 u = 315

1 u = 315 ÷ 105 = 3

Number of strawberries used to decorate all the small cakes
= 24 u
= 24 x 3
= 72

(c)
Number of strawberries to decorate one large cake
= 9 u
= 9 x 3
= 27

Number of remaining large cakes that were decorated yet
= 14 - 9
= 5

Number of more strawberries that Fiona needed to decorate the remaining large cakes
= 5 x 27
= 135

Answer(s): (a) 6; (b) 72; (c) 135