PSLE
Roshel baked a total of 33 large and small cakes in the ratio of 7 : 4. She decorated each cake with some strawberries in the ratio of 5 : 3. She used a total of 255 strawberries to decorate all the small cakes and 3 large cakes.

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

(a)
Fraction of the cakes that were large ones = ⁷_{7 + 4} = ⁷₁₁

Number of large cakes
= ⁷₁₁ x 33
= 21

Number of small cakes
= 33 - 21
= 12

	Large cakes	Small cakes	Total
Number	3	12
Value	5 u	3 u
Total value	15 u	36 u	51 u

(b)
Number of strawberries used to decorate 3 large cakes and 12 small cakes
= 15 u + 36 u
= 51 u

51 u = 255

1 u = 255 ÷ 51 = 5

Number of strawberries used to decorate all the small cakes
= 36 u
= 36 x 5
= 180

(c)
Number of strawberries to decorate one large cake
= 5 u
= 5 x 5
= 25

Number of remaining large cakes that were decorated yet
= 21 - 3
= 18

Number of more strawberries that Roshel needed to decorate the remaining large cakes
= 18 x 25
= 450

Answer(s): (a) 12; (b) 180; (c) 450