PSLE
Kathy baked a total of 40 large and small cakes in the ratio of 7 : 3. She decorated each cake with some lychees in the ratio of 9 : 5. She used a total of 264 lychees to decorate all the small cakes and 8 large cakes.

1. How many small cakes did Kathy bake?
2. What was the number of lychees used to decorate all the small cakes?
3. How many more lychees did Kathy 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 40
= 28

Number of small cakes
= 40 - 28
= 12

	Large cakes	Small cakes	Total
Number	8	12
Value	9 u	5 u
Total value	72 u	60 u	132 u

(b)
Number of lychees used to decorate 8 large cakes and 12 small cakes
= 72 u + 60 u
= 132 u

132 u = 264

1 u = 264 ÷ 132 = 2

Number of lychees used to decorate all the small cakes
= 60 u
= 60 x 2
= 120

(c)
Number of lychees to decorate one large cake
= 9 u
= 9 x 2
= 18

Number of remaining large cakes that were decorated yet
= 28 - 8
= 20

Number of more lychees that Kathy needed to decorate the remaining large cakes
= 20 x 18
= 360

Answer(s): (a) 12; (b) 120; (c) 360