The ratio of the number of green stickers to red stickers is 7 : 1.
After Adam buys another 35 red stickers and gives away 31 green stickers,
the ratio becomes of the number of green stickers to red stickers is 5 : 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 5 = (4) |
Before |
28 u |
7 u |
1 u |
5 u |
Change |
- 124 |
- 31 |
+ 35 |
+ 175 |
After |
20 p |
5 p |
4 p |
20 p |
7 u + 35 = 5 p --- (1)
1 u - 31 = 4 p --- (2)
Make p the same.
(1)
x 428 u - 124 = 20 p --- (3)
(2)
x 55 u + 175 = 20 p --- (4)
(3) = (4)
28 u - 124 = 5 u + 175
28 u - 5 u = 124 + 175
23 u = 299
1 u = 299 ÷ 23 = 13
Number of stickers that Adam have now
= 7 u + 35 + 1 u - 31
= 7 u + 1 u + 35 - 31
= 8 u + 4
= 8 x 13 + 4
= 104 + 4
= 108
Answer(s): 108