The ratio of the number of green stickers to blue stickers is 5 : 3.
After Adam gives away 19 green stickers and gives away 45 blue stickers,
the ratio becomes of the number of green stickers to blue stickers is 7 : 3.
How many stickers does Adam have now?
|
Make p the same (1) x 3 = (3) |
(1) Green |
(2) Blue |
Make p the same (2) x 7 = (4) |
Before |
15 u |
5 u |
3 u |
21 u |
Change |
- 57 |
- 19 |
- 45 |
- 315 |
After |
21 p |
7 p |
3 p |
21 p |
5 u - 19 = 7 p --- (1)
3 u - 45 = 3 p --- (2)
Make p the same.
(1) x 3
15 u - 57 = 21 p --- (3)
(2) x 7
21 u - 315 = 21 p --- (4)
(4) = (3)
21 u - 315 = 15 u - 57
21 u - 15 u = 315 - 57
6 u = 258
1 u = 258 ÷ 6 = 43
Number of stickers that Adam has now
= 5 u - 19 + 3 u - 45
= 8 u - 64
= 8 x 43 - 64
= 344 - 64
= 280
Answer(s): 280