The ratio of the number of green stickers to blue stickers is 8 : 1.
After Adam buys another 21 blue stickers and gives away 12 green stickers,
the ratio becomes of the number of green stickers to blue stickers is 7 : 2.
How many stickers does Adam have now?
|
Make p the same (1) x 2 = (3) |
(1) Green |
(2) Blue |
Make p the same (2) x 7 = (4) |
Before |
16 u |
8 u |
1 u |
7 u |
Change |
- 24 |
- 12 |
+ 21 |
+ 147 |
After |
14 p |
7 p |
2 p |
14 p |
8 u + 21 = 7 p --- (1)
1 u - 12 = 2 p --- (2)
Make p the same.
(1)
x 216 u - 24 = 14 p --- (3)
(2)
x 77 u + 147 = 14 p --- (4)
(3) = (4)
16 u - 24 = 7 u + 147
16 u - 7 u = 24 + 147
9 u = 171
1 u = 171 ÷ 9 = 19
Number of stickers that Adam have now
= 8 u + 21 + 1 u - 12
= 8 u + 1 u + 21 - 12
= 9 u + 9
= 9 x 19 + 9
= 171 + 9
= 180
Answer(s): 180