PSLE
Nora baked a total of 35 large and small cakes in the ratio of 5 : 2. She decorated each cake with some cherries in the ratio of 7 : 4. She used a total of 136 cherries to decorate all the small cakes and 4 large cakes.

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

(a)
Fraction of the cakes that were large ones = ⁵_{5 + 2} = ⁵₇

Number of large cakes
= ⁵₇ x 35
= 25

Number of small cakes
= 35 - 25
= 10

	Large cakes	Small cakes	Total
Number	4	10
Value	7 u	4 u
Total value	28 u	40 u	68 u

(b)
Number of cherries used to decorate 4 large cakes and 10 small cakes
= 28 u + 40 u
= 68 u

68 u = 136

1 u = 136 ÷ 68 = 2

Number of cherries used to decorate all the small cakes
= 40 u
= 40 x 2
= 80

(c)
Number of cherries to decorate one large cake
= 7 u
= 7 x 2
= 14

Number of remaining large cakes that were decorated yet
= 25 - 4
= 21

Number of more cherries that Nora needed to decorate the remaining large cakes
= 21 x 14
= 294

Answer(s): (a) 10; (b) 80; (c) 294