The ratio of the number of green stickers to red stickers is 5 : 1.
After Adam buys another 49 red stickers and gives away 19 green stickers,
the ratio becomes of the number of green stickers to red stickers is 9 : 4.
How many stickers does Adam have now?
|
Make p the same (1) x 4 = (3) |
(1) Green |
(2) Red |
Make p the same (2) x 9 = (4) |
Before |
20 u |
5 u |
1 u |
9 u |
Change |
- 76 |
- 19 |
+ 49 |
+ 441 |
After |
36 p |
9 p |
4 p |
36 p |
5 u + 49 = 9 p --- (1)
1 u - 19 = 4 p --- (2)
Make p the same.
(1)
x 420 u - 76 = 36 p --- (3)
(2)
x 99 u + 441 = 36 p --- (4)
(3) = (4)
20 u - 76 = 9 u + 441
20 u - 9 u = 76 + 441
11 u = 517
1 u = 517 ÷ 11 = 47
Number of stickers that Adam have now
= 5 u + 49 + 1 u - 19
= 5 u + 1 u + 49 - 19
= 6 u + 30
= 6 x 47 + 30
= 282 + 30
= 312
Answer(s): 312