The ratio of the number of blue stickers to green stickers is 9 : 7.
After Adam buys another 30 blue stickers and 40 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 |
54 u |
9 u |
7 u |
49 u |
Change |
+ 180 |
+ 30 |
+ 40 |
+ 280 |
After |
54 u + 180 |
9 u + 30 |
7 u + 40 |
49 u + 280 |
Comparing the blue stickers and the green stickers in the end |
42 p |
7 p |
6 p |
42 p |
9 u + 30 = 7 p --- (1)
7 u + 40 = 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 54 u + 180 = 42 p --- (3)
(2)
x 7 49 u + 280 = 42 p --- (4)
(3) = (4)
54 u + 180 = 49 u + 280
54 u - 49 u = 280 - 180
5 u = 100
1 u = 100 ÷ 5 = 20
Number of stickers that Adam has now
= 9 u + 30 + 7 u + 40
= 9 u + 7 u + 30 + 40
= 16 u + 70
= 16 x 20 + 70
= 320 + 70
= 390
Answer(s): 390