The ratio of the number of red stickers to green stickers is 7 : 2.
After Adam buys another 42 green stickers and gives away 17 red stickers,
the ratio becomes of the number of red stickers to green stickers is 3 : 2.
How many stickers does Adam have now?
|
Make p the same (1) x 2 = (3) |
(1) Red |
(2) Green |
Make p the same (2) x 3 = (4) |
Before |
14 u |
7 u |
2 u |
6 u |
Change |
- 34 |
- 17 |
+ 42 |
+ 126 |
After |
6 p |
3 p |
2 p |
6 p |
7 u + 42 = 3 p --- (1)
2 u - 17 = 2 p --- (2)
Make p the same.
(1)
x 214 u - 34 = 6 p --- (3)
(2)
x 36 u + 126 = 6 p --- (4)
(3) = (4)
14 u - 34 = 6 u + 126
14 u - 6 u = 34 + 126
8 u = 160
1 u = 160 ÷ 8 = 20
Number of stickers that Adam have now
= 7 u + 42 + 2 u - 17
= 7 u + 2 u + 42 - 17
= 9 u + 25
= 9 x 20 + 25
= 180 + 25
= 205
Answer(s): 205