The ratio of the number of green stickers to red stickers is 3 : 2.
After Adam buys another 70 green stickers and 80 red stickers,
the ratio becomes of the number of green stickers to red stickers is 7 : 6.
How many stickers does Adam have now?
|
Make p the same (1) x 6 = (3) |
(1) Green |
(2) Red |
Make p the same (2) x 7 = (4) |
Before |
18 u |
3 u |
2 u |
14 u |
Change |
+ 420 |
+ 70 |
+ 80 |
+ 560 |
After |
18 u + 420 |
3 u + 70 |
2 u + 80 |
14 u + 560 |
Comparing the green stickers and the red stickers in the end |
42 p |
7 p |
6 p |
42 p |
3 u + 70 = 7 p --- (1)
2 u + 80 = 6 p --- (2)
Make p the same by using the LCM of 6 and 7.
LCM of 6 and 7 is 42.
(1)
x 6 18 u + 420 = 42 p --- (3)
(2)
x 7 14 u + 560 = 42 p --- (4)
(3) = (4)
18 u + 420 = 14 u + 560
18 u - 14 u = 560 - 420
4 u = 140
1 u = 140 ÷ 4 = 35
Number of stickers that Adam has now
= 3 u + 70 + 2 u + 80
= 3 u + 2 u + 70 + 80
= 5 u + 150
= 5 x 35 + 150
= 175 + 150
= 325
Answer(s): 325