The ratio of the number of green stickers to red stickers is 3 : 1.
After Adam buys another 29 red stickers and gives away 28 green stickers,
the ratio becomes of the number of green stickers to red stickers is 7 : 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 7 = (4) |
Before |
12 u |
3 u |
1 u |
7 u |
Change |
- 112 |
- 28 |
+ 29 |
+ 203 |
After |
28 p |
7 p |
4 p |
28 p |
3 u + 29 = 7 p --- (1)
1 u - 28 = 4 p --- (2)
Make p the same.
(1)
x 412 u - 112 = 28 p --- (3)
(2)
x 77 u + 203 = 28 p --- (4)
(3) = (4)
12 u - 112 = 7 u + 203
12 u - 7 u = 112 + 203
5 u = 315
1 u = 315 ÷ 5 = 63
Number of stickers that Adam have now
= 3 u + 29 + 1 u - 28
= 3 u + 1 u + 29 - 28
= 4 u + 1
= 4 x 63 + 1
= 252 + 1
= 253
Answer(s): 253