PSLE Sarah baked a total of 40 large and small cakes in the ratio of 7 : 3. She decorated each cake with some lychees in the ratio of 9 : 5. She used a total of 348 lychees to decorate all the small cakes and 3 large cakes.
- How many small cakes did Sarah bake?
- What was the number of lychees used to decorate all the small cakes?
- How many more lychees did Sarah need to decorate the remaining large cakes?
(a)
Fraction of the cakes that were large ones =
77 + 3 =
710Number of large cakes
=
710 x 40
= 28
Number of small cakes
= 40 - 28
= 12
|
Large cakes |
Small cakes |
Total |
Number |
3 |
12 |
|
Value |
9 u |
5 u |
|
Total value |
27 u |
60 u |
87 u |
(b)
Number of lychees used to decorate 3 large cakes and 12 small cakes
= 27 u + 60 u
= 87 u
87 u = 348
1 u = 348 ÷ 87 = 4
Number of lychees used to decorate all the small cakes
= 60 u
= 60 x 4
= 240
(c)
Number of lychees to decorate one large cake
= 9 u
= 9 x 4
= 36
Number of remaining large cakes that were decorated yet
= 28 - 3
= 25
Number of more lychees that Sarah needed to decorate the remaining large cakes
= 25 x 36
= 900
Answer(s): (a) 12; (b) 240; (c) 900