Adam and Bryan have some stickers in the ratio of 3 : 4.
When Adam gives away 81 stickers,
the ratio of the stickers becomes 3 : 7.
- How many stickers do they have at first?
- How many stickers do they have in the end?
|
Adam |
Bryan |
Before |
3 x 7 = 21 u |
4 x 7 = 28 u |
Change |
- 81 |
No change |
After |
3 x 4 = 12 u |
7 x 4 = 28 u |
(a)
The number of stickers that Bryan has remains unchanged.
Make the number of stickers that Bryan has the same using LCM of 4 and 7.
LCM of 4 and 7 = 28
Number of stickers that Adam gives away
= 21 u - 12 u
= 9 u
9 u = 81
1 u = 81 ÷ 9 = 9
Number of stickers that they have at first
= 21 u + 28 u
= 49 u
= 49 x 9
= 441
(b)
Number of stickers that they have in the end
= 12 u + 28 u
= 40 u
= 40 x 9
= 360
Answer(s): (a) 441; (b) 360