The ratio of the number of red stickers to green stickers is 3 : 1.
After Adam gives away 42 red stickers and gives away 61 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 |
6 u |
3 u |
1 u |
9 u |
Change |
- 84 |
- 42 |
- 61 |
- 549 |
After |
18 p |
9 p |
2 p |
18 p |
3 u - 42 = 9 p --- (1)
1 u - 61 = 2 p --- (2)
Make p the same.
(1) x 2
6 u - 84 = 18 p --- (3)
(2) x 9
9 u - 549 = 18 p --- (4)
(4) = (3)
9 u - 549 = 6 u - 84
9 u - 6 u = 549 - 84
3 u = 465
1 u = 465 ÷ 3 = 155
Number of stickers that Adam has now
= 3 u - 42 + 1 u - 61
= 4 u - 103
= 4 x 155 - 103
= 620 - 103
= 517
Answer(s): 517