The ratio of the number of blue stickers to red stickers is 4 : 1.
After Adam buys another 29 red stickers and gives away 19 blue stickers,
the ratio becomes of the number of blue stickers to red stickers is 7 : 3.
How many stickers does Adam have now?
|
Make p the same (1) x 3 = (3) |
(1) Blue |
(2) Red |
Make p the same (2) x 7 = (4) |
Before |
12 u |
4 u |
1 u |
7 u |
Change |
- 57 |
- 19 |
+ 29 |
+ 203 |
After |
21 p |
7 p |
3 p |
21 p |
4 u + 29 = 7 p --- (1)
1 u - 19 = 3 p --- (2)
Make p the same.
(1)
x 312 u - 57 = 21 p --- (3)
(2)
x 77 u + 203 = 21 p --- (4)
(3) = (4)
12 u - 57 = 7 u + 203
12 u - 7 u = 57 + 203
5 u = 260
1 u = 260 ÷ 5 = 52
Number of stickers that Adam have now
= 4 u + 29 + 1 u - 19
= 4 u + 1 u + 29 - 19
= 5 u + 10
= 5 x 52 + 10
= 260 + 10
= 270
Answer(s): 270