The ratio of the number of blue stickers to green stickers is 4 : 3.
After Adam gives away 63 blue stickers and gives away 90 green stickers,
the ratio becomes of the number of blue stickers to green stickers is 7 : 3.
How many stickers does Adam have now?
|
Make p the same (1) x 3 = (3) |
(1) Blue |
(2) Green |
Make p the same (2) x 7 = (4) |
Before |
12 u |
4 u |
3 u |
21 u |
Change |
- 189 |
- 63 |
- 90 |
- 630 |
After |
21 p |
7 p |
3 p |
21 p |
4 u - 63 = 7 p --- (1)
3 u - 90 = 3 p --- (2)
Make p the same.
(1) x 3
12 u - 189 = 21 p --- (3)
(2) x 7
21 u - 630 = 21 p --- (4)
(4) = (3)
21 u - 630 = 12 u - 189
21 u - 12 u = 630 - 189
9 u = 441
1 u = 441 ÷ 9 = 49
Number of stickers that Adam has now
= 4 u - 63 + 3 u - 90
= 7 u - 153
= 7 x 49 - 153
= 343 - 153
= 190
Answer(s): 190