The ratio of the number of red stickers to green stickers is 3 : 2.
After Adam gives away 31 red stickers and gives away 38 green stickers,
the ratio becomes of the number of red stickers to green stickers is 5 : 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 5 = (4) |
Before |
6 u |
3 u |
2 u |
10 u |
Change |
- 62 |
- 31 |
- 38 |
- 190 |
After |
10 p |
5 p |
2 p |
10 p |
3 u - 31 = 5 p --- (1)
2 u - 38 = 2 p --- (2)
Make p the same.
(1) x 2
6 u - 62 = 10 p --- (3)
(2) x 5
10 u - 190 = 10 p --- (4)
(4) = (3)
10 u - 190 = 6 u - 62
10 u - 6 u = 190 - 62
4 u = 128
1 u = 128 ÷ 4 = 32
Number of stickers that Adam has now
= 3 u - 31 + 2 u - 38
= 5 u - 69
= 5 x 32 - 69
= 160 - 69
= 91
Answer(s): 91