PSLE Barbara baked a total of 42 large and small cakes in the ratio of 4 : 3. She decorated each cake with some grapes in the ratio of 5 : 2. She used a total of 132 grapes to decorate all the small cakes and 6 large cakes.
- How many small cakes did Barbara bake?
- What was the number of grapes used to decorate all the small cakes?
- How many more grapes did Barbara need to decorate the remaining large cakes?
(a)
Fraction of the cakes that were large ones =
44 + 3 =
47Number of large cakes
=
47 x 42
= 24
Number of small cakes
= 42 - 24
= 18
|
Large cakes |
Small cakes |
Total |
Number |
6 |
18 |
|
Value |
5 u |
2 u |
|
Total value |
30 u |
36 u |
66 u |
(b)
Number of grapes used to decorate 6 large cakes and 18 small cakes
= 30 u + 36 u
= 66 u
66 u = 132
1 u = 132 ÷ 66 = 2
Number of grapes used to decorate all the small cakes
= 36 u
= 36 x 2
= 72
(c)
Number of grapes to decorate one large cake
= 5 u
= 5 x 2
= 10
Number of remaining large cakes that were decorated yet
= 24 - 6
= 18
Number of more grapes that Barbara needed to decorate the remaining large cakes
= 18 x 10
= 180
Answer(s): (a) 18; (b) 72; (c) 180