PSLE Gillian baked a total of 49 large and small cakes in the ratio of 5 : 2. She decorated each cake with some grapes in the ratio of 3 : 2. She used a total of 430 grapes to decorate all the small cakes and 5 large cakes.
- How many small cakes did Gillian bake?
- What was the number of grapes used to decorate all the small cakes?
- How many more grapes did Gillian need to decorate the remaining large cakes?
(a)
Fraction of the cakes that were large ones =
55 + 2 =
57Number of large cakes
=
57 x 49
= 35
Number of small cakes
= 49 - 35
= 14
|
Large cakes |
Small cakes |
Total |
Number |
5 |
14 |
|
Value |
3 u |
2 u |
|
Total value |
15 u |
28 u |
43 u |
(b)
Number of grapes used to decorate 5 large cakes and 14 small cakes
= 15 u + 28 u
= 43 u
43 u = 430
1 u = 430 ÷ 43 = 10
Number of grapes used to decorate all the small cakes
= 28 u
= 28 x 10
= 280
(c)
Number of grapes to decorate one large cake
= 3 u
= 3 x 10
= 30
Number of remaining large cakes that were decorated yet
= 35 - 5
= 30
Number of more grapes that Gillian needed to decorate the remaining large cakes
= 30 x 30
= 900
Answer(s): (a) 14; (b) 280; (c) 900