The ratio of the number of green stickers to red stickers is 5 : 1.
After Adam buys another 31 red stickers and gives away 16 green stickers,
the ratio becomes of the number of green stickers to red stickers is 7 : 2.
How many stickers does Adam have now?
|
Make p the same (1) x 2 = (3) |
(1) Green |
(2) Red |
Make p the same (2) x 7 = (4) |
Before |
10 u |
5 u |
1 u |
7 u |
Change |
- 32 |
- 16 |
+ 31 |
+ 217 |
After |
14 p |
7 p |
2 p |
14 p |
5 u + 31 = 7 p --- (1)
1 u - 16 = 2 p --- (2)
Make p the same.
(1)
x 210 u - 32 = 14 p --- (3)
(2)
x 77 u + 217 = 14 p --- (4)
(3) = (4)
10 u - 32 = 7 u + 217
10 u - 7 u = 32 + 217
3 u = 249
1 u = 249 ÷ 3 = 83
Number of stickers that Adam have now
= 5 u + 31 + 1 u - 16
= 5 u + 1 u + 31 - 16
= 6 u + 15
= 6 x 83 + 15
= 498 + 15
= 513
Answer(s): 513