The ratio of the number of blue stickers to red stickers is 3 : 2.
After Adam gives away 75 blue stickers and gives away 90 red stickers,
the ratio becomes of the number of blue stickers to red stickers is 9 : 4.
How many stickers does Adam have now?
|
Make p the same (1) x 4 = (3) |
(1) Blue |
(2) Red |
Make p the same (2) x 9 = (4) |
Before |
12 u |
3 u |
2 u |
18 u |
Change |
- 300 |
- 75 |
- 90 |
- 810 |
After |
36 p |
9 p |
4 p |
36 p |
3 u - 75 = 9 p --- (1)
2 u - 90 = 4 p --- (2)
Make p the same.
(1) x 4
12 u - 300 = 36 p --- (3)
(2) x 9
18 u - 810 = 36 p --- (4)
(4) = (3)
18 u - 810 = 12 u - 300
18 u - 12 u = 810 - 300
6 u = 510
1 u = 510 ÷ 6 = 85
Number of stickers that Adam has now
= 3 u - 75 + 2 u - 90
= 5 u - 165
= 5 x 85 - 165
= 425 - 165
= 260
Answer(s): 260