Adam and Bryan have some stickers in the ratio of 7 : 6.
When Adam buys another 21 stickers,
the ratio of the stickers becomes 7 : 4.
- How many stickers do they have at first?
- How many stickers do they have in the end?
|
Charlie |
Adam |
Before |
7 x 2 = 14 u |
6 x 2 = 12 u |
Change |
+ 21 |
No change |
After |
7 x 3 = 21 u |
4 x 3 = 12 u |
(a)
The number of stickers that Adam has remains unchanged.
Make the number of stickers that Adam has the same using LCM of 6 and 4.
LCM of 6 and 4 = 12
Number of stickers that Charlie buys
= 21 u - 14 u
= 7 u
7 u = 21
1 u = 21 ÷ 7 = 3
Number of stickers that they have at first
= 14 u + 12 u
= 26 u
= 26 x 3
= 78
(b)
Number of stickers that they have in the end
= 21 u + 12 u
= 33 u
= 33 x 3
= 99
Answer(s): (a) 78; (b) 99