The ratio of the number of red stickers to green stickers is 7 : 3.
After Adam gives away 65 red stickers and gives away 39 green stickers,
the ratio becomes of the number of red stickers to green stickers is 8 : 3.
How many stickers does Adam have now?
|
Make p the same (1) x 3 = (3) |
(1) Red |
(2) Green |
Make p the same (2) x 8 = (4) |
Before |
21 u |
7 u |
3 u |
24 u |
Change |
- 195 |
- 65 |
- 39 |
- 312 |
After |
24 p |
8 p |
3 p |
24 p |
7 u - 65 = 8 p --- (1)
3 u - 39 = 3 p --- (2)
Make p the same.
(1) x 3
21 u - 195 = 24 p --- (3)
(2) x 8
24 u - 312 = 24 p --- (4)
(4) = (3)
24 u - 312 = 21 u - 195
24 u - 21 u = 312 - 195
3 u = 117
1 u = 117 ÷ 3 = 39
Number of stickers that Adam has now
= 7 u - 65 + 3 u - 39
= 10 u - 104
= 10 x 39 - 104
= 390 - 104
= 286
Answer(s): 286