The ratio of the number of red stickers to blue stickers is 7 : 2.
After Adam buys another 40 blue stickers and gives away 12 red stickers,
the ratio becomes of the number of red stickers to blue stickers is 5 : 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 5 = (4) |
Before |
14 u |
7 u |
2 u |
10 u |
Change |
- 24 |
- 12 |
+ 40 |
+ 200 |
After |
10 p |
5 p |
2 p |
10 p |
7 u + 40 = 5 p --- (1)
2 u - 12 = 2 p --- (2)
Make p the same.
(1)
x 214 u - 24 = 10 p --- (3)
(2)
x 510 u + 200 = 10 p --- (4)
(3) = (4)
14 u - 24 = 10 u + 200
14 u - 10 u = 24 + 200
4 u = 224
1 u = 224 ÷ 4 = 56
Number of stickers that Adam have now
= 7 u + 40 + 2 u - 12
= 7 u + 2 u + 40 - 12
= 9 u + 28
= 9 x 56 + 28
= 504 + 28
= 532
Answer(s): 532