The ratio of the number of green stickers to blue stickers is 5 : 3.
After Adam gives away 24 green stickers and gives away 90 blue stickers,
the ratio becomes of the number of green stickers to blue stickers is 7 : 3.
How many stickers does Adam have now?
|
Make p the same (1) x 3 = (3) |
(1) Green |
(2) Blue |
Make p the same (2) x 7 = (4) |
Before |
15 u |
5 u |
3 u |
21 u |
Change |
- 72 |
- 24 |
- 90 |
- 630 |
After |
21 p |
7 p |
3 p |
21 p |
5 u - 24 = 7 p --- (1)
3 u - 90 = 3 p --- (2)
Make p the same.
(1) x 3
15 u - 72 = 21 p --- (3)
(2) x 7
21 u - 630 = 21 p --- (4)
(4) = (3)
21 u - 630 = 15 u - 72
21 u - 15 u = 630 - 72
6 u = 558
1 u = 558 ÷ 6 = 93
Number of stickers that Adam has now
= 5 u - 24 + 3 u - 90
= 8 u - 114
= 8 x 93 - 114
= 744 - 114
= 630
Answer(s): 630