Adam and Bryan have some stickers in the ratio of 2 : 5.
When Adam buys another 12 stickers,
the ratio of the stickers becomes 4 : 7.
- How many stickers do they have at first?
- How many stickers do they have in the end?
|
Bryan |
Adam |
Before |
2 x 7 = 14 u |
5 x 7 = 35 u |
Change |
+ 12 |
No change |
After |
4 x 5 = 20 u |
7 x 5 = 35 u |
(a)
The number of stickers that Adam has remains unchanged.
Make the number of stickers that Adam has the same using LCM of 5 and 7.
LCM of 5 and 7 = 35
Number of stickers that Bryan buys
= 20 u - 14 u
= 6 u
6 u = 12
1 u = 12 ÷ 6 = 2
Number of stickers that they have at first
= 14 u + 35 u
= 49 u
= 49 x 2
= 98
(b)
Number of stickers that they have in the end
= 20 u + 35 u
= 55 u
= 55 x 2
= 110
Answer(s): (a) 98; (b) 110