The ratio of the number of red stickers to blue stickers is 7 : 2.
After Adam gives away 31 red stickers and gives away 58 blue stickers,
the ratio becomes of the number of red stickers to blue stickers is 9 : 2.
How many stickers does Adam have now?
|
Make p the same (1) x 2 = (3) |
(1) Red |
(2) Blue |
Make p the same (2) x 9 = (4) |
Before |
14 u |
7 u |
2 u |
18 u |
Change |
- 62 |
- 31 |
- 58 |
- 522 |
After |
18 p |
9 p |
2 p |
18 p |
7 u - 31 = 9 p --- (1)
2 u - 58 = 2 p --- (2)
Make p the same.
(1) x 2
14 u - 62 = 18 p --- (3)
(2) x 9
18 u - 522 = 18 p --- (4)
(4) = (3)
18 u - 522 = 14 u - 62
18 u - 14 u = 522 - 62
4 u = 460
1 u = 460 ÷ 4 = 115
Number of stickers that Adam has now
= 7 u - 31 + 2 u - 58
= 9 u - 89
= 9 x 115 - 89
= 1035 - 89
= 946
Answer(s): 946