The ratio of the number of green stickers to blue stickers is 7 : 2.
After Adam buys another 60 green stickers and 80 blue stickers,
the ratio becomes of the number of green stickers to blue stickers is 5 : 3.
How many stickers does Adam have now?
|
Make p the same (1) x 3 = (3) |
(1) Green |
(2) Blue |
Make p the same (2) x 5 = (4) |
Before |
21 u |
7 u |
2 u |
10 u |
Change |
+ 180 |
+ 60 |
+ 80 |
+ 400 |
After |
21 u + 180 |
7 u + 60 |
2 u + 80 |
10 u + 400 |
Comparing the green stickers and the blue stickers in the end |
15 p |
5 p |
3 p |
15 p |
7 u + 60 = 5 p --- (1)
2 u + 80 = 3 p --- (2)
Make p the same by using the LCM of 3 and 5.
LCM of 3 and 5 is 15.
(1)
x 3 21 u + 180 = 15 p --- (3)
(2)
x 5 10 u + 400 = 15 p --- (4)
(3) = (4)
21 u + 180 = 10 u + 400
21 u - 10 u = 400 - 180
11 u = 220
1 u = 220 ÷ 11 = 20
Number of stickers that Adam has now
= 7 u + 60 + 2 u + 80
= 7 u + 2 u + 60 + 80
= 9 u + 140
= 9 x 20 + 140
= 180 + 140
= 320
Answer(s): 320