The ratio of the number of blue stickers to red stickers is 3 : 2.
After Adam gives away 18 blue stickers and gives away 62 red 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 |
9 u |
3 u |
2 u |
14 u |
Change |
- 54 |
- 18 |
- 62 |
- 434 |
After |
21 p |
7 p |
3 p |
21 p |
3 u - 18 = 7 p --- (1)
2 u - 62 = 3 p --- (2)
Make p the same.
(1) x 3
9 u - 54 = 21 p --- (3)
(2) x 7
14 u - 434 = 21 p --- (4)
(4) = (3)
14 u - 434 = 9 u - 54
14 u - 9 u = 434 - 54
5 u = 380
1 u = 380 ÷ 5 = 76
Number of stickers that Adam has now
= 3 u - 18 + 2 u - 62
= 5 u - 80
= 5 x 76 - 80
= 380 - 80
= 300
Answer(s): 300