The ratio of the number of blue stickers to green stickers is 5 : 3.
After Adam gives away 56 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 |
15 u |
5 u |
3 u |
21 u |
Change |
- 168 |
- 56 |
- 90 |
- 630 |
After |
21 p |
7 p |
3 p |
21 p |
5 u - 56 = 7 p --- (1)
3 u - 90 = 3 p --- (2)
Make p the same.
(1) x 3
15 u - 168 = 21 p --- (3)
(2) x 7
21 u - 630 = 21 p --- (4)
(4) = (3)
21 u - 630 = 15 u - 168
21 u - 15 u = 630 - 168
6 u = 462
1 u = 462 ÷ 6 = 77
Number of stickers that Adam has now
= 5 u - 56 + 3 u - 90
= 8 u - 146
= 8 x 77 - 146
= 616 - 146
= 470
Answer(s): 470