The ratio of the number of red stickers to blue stickers is 3 : 2.
After Adam gives away 69 red stickers and gives away 64 blue stickers,
the ratio becomes of the number of red stickers to blue stickers is 7 : 4.
How many stickers does Adam have now?
|
Make p the same (1) x 4 = (3) |
(1) Red |
(2) Blue |
Make p the same (2) x 7 = (4) |
Before |
12 u |
3 u |
2 u |
14 u |
Change |
- 276 |
- 69 |
- 64 |
- 448 |
After |
28 p |
7 p |
4 p |
28 p |
3 u - 69 = 7 p --- (1)
2 u - 64 = 4 p --- (2)
Make p the same.
(1) x 4
12 u - 276 = 28 p --- (3)
(2) x 7
14 u - 448 = 28 p --- (4)
(4) = (3)
14 u - 448 = 12 u - 276
14 u - 12 u = 448 - 276
2 u = 172
1 u = 172 ÷ 2 = 86
Number of stickers that Adam has now
= 3 u - 69 + 2 u - 64
= 5 u - 133
= 5 x 86 - 133
= 430 - 133
= 297
Answer(s): 297