The ratio of the number of red stickers to green stickers is 5 : 2.
After Adam gives away 18 red stickers and gives away 52 green stickers,
the ratio becomes of the number of red stickers to green stickers is 9 : 2.
How many stickers does Adam have now?
|
Make p the same (1) x 2 = (3) |
(1) Red |
(2) Green |
Make p the same (2) x 9 = (4) |
Before |
10 u |
5 u |
2 u |
18 u |
Change |
- 36 |
- 18 |
- 52 |
- 468 |
After |
18 p |
9 p |
2 p |
18 p |
5 u - 18 = 9 p --- (1)
2 u - 52 = 2 p --- (2)
Make p the same.
(1) x 2
10 u - 36 = 18 p --- (3)
(2) x 9
18 u - 468 = 18 p --- (4)
(4) = (3)
18 u - 468 = 10 u - 36
18 u - 10 u = 468 - 36
8 u = 432
1 u = 432 ÷ 8 = 54
Number of stickers that Adam has now
= 5 u - 18 + 2 u - 52
= 7 u - 70
= 7 x 54 - 70
= 378 - 70
= 308
Answer(s): 308