Five hours ago, a grocer started his day with some oranges and starfruits in the ratio of 7 : 2. There were 100 starfruits. Some of the oranges were bought by Fiona. As a result, the number of oranges became
25 of the starfruits.
- How many oranges did the grocer have left?
- How many oranges did the grocer have to buy in order to have an equal number of oranges and starfruits?
|
Oranges |
Starfruits |
Before |
7x5 = 35 u |
2x5 = 10 u |
Change |
- ? |
|
After |
2x2 = 4 u |
5x2 = 10 u |
(a)
The number of starfruits remains unchanged. Make the number of starfruits the same. LCM of 2 and 5 is 10.
10 u = 100
1 u = 100 ÷ 10 = 10
Number of oranges that the grocer had left
= 4 u
= 4 x 10
= 40
(b)
Number of oranges that the grocer had to buy to have an equal number of oranges and starfruits
= 10 u - 4 u
= 6 u
= 6 x 10
= 60
Answer(s): (a) 40; (b) 60