The ratio of the number of red stickers to green stickers is 3 : 2.
After Adam gives away 90 red stickers and gives away 32 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 |
2 u |
18 u |
Change |
- 180 |
- 90 |
- 32 |
- 288 |
After |
18 p |
9 p |
2 p |
18 p |
3 u - 90 = 9 p --- (1)
2 u - 32 = 2 p --- (2)
Make p the same.
(1) x 2
6 u - 180 = 18 p --- (3)
(2) x 9
18 u - 288 = 18 p --- (4)
(4) = (3)
18 u - 288 = 6 u - 180
18 u - 6 u = 288 - 180
12 u = 108
1 u = 108 ÷ 12 = 9
Number of stickers that Adam has now
= 3 u - 90 + 2 u - 32
= 5 u - 122
= 5 x 9 - 122
= 45 - 122
= -77
Answer(s): -77