The ratio of the number of blue stickers to red stickers is 3 : 1.
After Adam gives away 72 blue stickers and gives away 79 red stickers,
the ratio becomes of the number of blue stickers to red stickers is 9 : 2.
How many stickers does Adam have now?
|
Make p the same (1) x 2 = (3) |
(1) Blue |
(2) Red |
Make p the same (2) x 9 = (4) |
Before |
6 u |
3 u |
1 u |
9 u |
Change |
- 144 |
- 72 |
- 79 |
- 711 |
After |
18 p |
9 p |
2 p |
18 p |
3 u - 72 = 9 p --- (1)
1 u - 79 = 2 p --- (2)
Make p the same.
(1) x 2
6 u - 144 = 18 p --- (3)
(2) x 9
9 u - 711 = 18 p --- (4)
(4) = (3)
9 u - 711 = 6 u - 144
9 u - 6 u = 711 - 144
3 u = 567
1 u = 567 ÷ 3 = 189
Number of stickers that Adam has now
= 3 u - 72 + 1 u - 79
= 4 u - 151
= 4 x 189 - 151
= 756 - 151
= 605
Answer(s): 605