The ratio of the number of red stickers to green stickers is 4 : 3.
After Adam gives away 24 red stickers and gives away 81 green stickers,
the ratio becomes of the number of red stickers to green stickers is 5 : 3.
How many stickers does Adam have now?
|
Make p the same (1) x 3 = (3) |
(1) Red |
(2) Green |
Make p the same (2) x 5 = (4) |
Before |
12 u |
4 u |
3 u |
15 u |
Change |
- 72 |
- 24 |
- 81 |
- 405 |
After |
15 p |
5 p |
3 p |
15 p |
4 u - 24 = 5 p --- (1)
3 u - 81 = 3 p --- (2)
Make p the same.
(1) x 3
12 u - 72 = 15 p --- (3)
(2) x 5
15 u - 405 = 15 p --- (4)
(4) = (3)
15 u - 405 = 12 u - 72
15 u - 12 u = 405 - 72
3 u = 333
1 u = 333 ÷ 3 = 111
Number of stickers that Adam has now
= 4 u - 24 + 3 u - 81
= 7 u - 105
= 7 x 111 - 105
= 777 - 105
= 672
Answer(s): 672