PSLE
Fanny baked a total of 35 large and small cakes in the ratio of 4 : 3. She decorated each cake with some cranberries in the ratio of 5 : 3. She used a total of 420 cranberries to decorate all the small cakes and 5 large cakes.

1. How many small cakes did Fanny bake?
2. What was the number of cranberries used to decorate all the small cakes?
3. How many more cranberries did Fanny 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 35
= 20

Number of small cakes
= 35 - 20
= 15

	Large cakes	Small cakes	Total
Number	5	15
Value	5 u	3 u
Total value	25 u	45 u	70 u

(b)
Number of cranberries used to decorate 5 large cakes and 15 small cakes
= 25 u + 45 u
= 70 u

70 u = 420

1 u = 420 ÷ 70 = 6

Number of cranberries used to decorate all the small cakes
= 45 u
= 45 x 6
= 270

(c)
Number of cranberries to decorate one large cake
= 5 u
= 5 x 6
= 30

Number of remaining large cakes that were decorated yet
= 20 - 5
= 15

Number of more cranberries that Fanny needed to decorate the remaining large cakes
= 15 x 30
= 450

Answer(s): (a) 15; (b) 270; (c) 450