The ratio of the number of green stickers to red stickers is 5 : 2.
After Adam gives away 78 green stickers and gives away 92 red stickers,
the ratio becomes of the number of green stickers to red stickers is 9 : 2.
How many stickers does Adam have now?
|
Make p the same (1) x 2 = (3) |
(1) Green |
(2) Red |
Make p the same (2) x 9 = (4) |
Before |
10 u |
5 u |
2 u |
18 u |
Change |
- 156 |
- 78 |
- 92 |
- 828 |
After |
18 p |
9 p |
2 p |
18 p |
5 u - 78 = 9 p --- (1)
2 u - 92 = 2 p --- (2)
Make p the same.
(1) x 2
10 u - 156 = 18 p --- (3)
(2) x 9
18 u - 828 = 18 p --- (4)
(4) = (3)
18 u - 828 = 10 u - 156
18 u - 10 u = 828 - 156
8 u = 672
1 u = 672 ÷ 8 = 84
Number of stickers that Adam has now
= 5 u - 78 + 2 u - 92
= 7 u - 170
= 7 x 84 - 170
= 588 - 170
= 418
Answer(s): 418