PSLE Lina baked a total of 24 large and small cakes in the ratio of 7 : 5. She decorated each cake with some grapes in the ratio of 3 : 2. She used a total of 369 grapes to decorate all the small cakes and 7 large cakes.
- How many small cakes did Lina bake?
- What was the number of grapes used to decorate all the small cakes?
- How many more grapes did Lina need to decorate the remaining large cakes?
(a)
Number of large cakes
=
712 x 24
= 14
Number of small cakes
= 24 - 14
= 10
|
Large cakes |
Small cakes |
Total |
Number |
7 |
10 |
|
Value |
3 u |
2 u |
|
Total value |
21 u |
20 u |
41 u |
(b)
Number of grapes used to decorate 7 large cakes and 10 small cakes
= 21 u + 20 u
= 41 u
41 u = 369
1 u = 369 ÷ 41 = 9
Number of grapes used to decorate all the small cakes
= 20 u
= 20 x 9
= 180
(c)
Number of grapes to decorate one large cake
= 3 u
= 3 x 9
= 27
Number of remaining large cakes that were decorated yet
= 14 - 7
= 7
Number of more grapes that Lina needed to decorate the remaining large cakes
= 7 x 27
= 189
Answer(s): (a) 10; (b) 180; (c) 189