The ratio of the number of red stickers to green stickers is 7 : 1.
After Adam buys another 50 green stickers and gives away 42 red stickers,
the ratio becomes of the number of red stickers to green stickers is 7 : 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 7 = (4) |
Before |
14 u |
7 u |
1 u |
7 u |
Change |
- 84 |
- 42 |
+ 50 |
+ 350 |
After |
14 p |
7 p |
2 p |
14 p |
7 u + 50 = 7 p --- (1)
1 u - 42 = 2 p --- (2)
Make p the same.
(1)
x 214 u - 84 = 14 p --- (3)
(2)
x 77 u + 350 = 14 p --- (4)
(3) = (4)
14 u - 84 = 7 u + 350
14 u - 7 u = 84 + 350
7 u = 434
1 u = 434 ÷ 7 = 62
Number of stickers that Adam have now
= 7 u + 50 + 1 u - 42
= 7 u + 1 u + 50 - 42
= 8 u + 8
= 8 x 62 + 8
= 496 + 8
= 504
Answer(s): 504