The ratio of the number of red stickers to blue stickers is 4 : 3.
After Adam gives away 12 red stickers and gives away 54 blue stickers,
the ratio becomes of the number of red stickers to blue stickers is 7 : 3.
How many stickers does Adam have now?
|
Make p the same (1) x 3 = (3) |
(1) Red |
(2) Blue |
Make p the same (2) x 7 = (4) |
Before |
12 u |
4 u |
3 u |
21 u |
Change |
- 36 |
- 12 |
- 54 |
- 378 |
After |
21 p |
7 p |
3 p |
21 p |
4 u - 12 = 7 p --- (1)
3 u - 54 = 3 p --- (2)
Make p the same.
(1) x 3
12 u - 36 = 21 p --- (3)
(2) x 7
21 u - 378 = 21 p --- (4)
(4) = (3)
21 u - 378 = 12 u - 36
21 u - 12 u = 378 - 36
9 u = 342
1 u = 342 ÷ 9 = 38
Number of stickers that Adam has now
= 4 u - 12 + 3 u - 54
= 7 u - 66
= 7 x 38 - 66
= 266 - 66
= 200
Answer(s): 200