The ratio of the number of blue stickers to green stickers is 2 : 1.
After Adam buys another 10 blue stickers and 20 green stickers,
the ratio becomes of the number of blue stickers to green stickers is 7 : 6.
How many stickers does Adam have now?
|
Make p the same (1) x 6 = (3) |
(1) Blue |
(2) Green |
Make p the same (2) x 7 = (4) |
Before |
12 u |
2 u |
1 u |
7 u |
Change |
+ 60 |
+ 10 |
+ 20 |
+ 140 |
After |
12 u + 60 |
2 u + 10 |
1 u + 20 |
7 u + 140 |
Comparing the blue stickers and the green stickers in the end |
42 p |
7 p |
6 p |
42 p |
2 u + 10 = 7 p --- (1)
1 u + 20 = 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 12 u + 60 = 42 p --- (3)
(2)
x 7 7 u + 140 = 42 p --- (4)
(3) = (4)
12 u + 60 = 7 u + 140
12 u - 7 u = 140 - 60
5 u = 80
1 u = 80 ÷ 5 = 16
Number of stickers that Adam has now
= 2 u + 10 + 1 u + 20
= 2 u + 1 u + 10 + 20
= 3 u + 30
= 3 x 16 + 30
= 48 + 30
= 78
Answer(s): 78