The ratio of the number of blue stickers to green stickers is 7 : 4.
After Adam buys another 70 blue stickers and 80 green stickers,
the ratio becomes of the number of blue stickers to green stickers is 7 : 5.
How many stickers does Adam have now?
|
Make p the same (1) x 5 = (3) |
(1) Blue |
(2) Green |
Make p the same (2) x 7 = (4) |
Before |
35 u |
7 u |
4 u |
28 u |
Change |
+ 350 |
+ 70 |
+ 80 |
+ 560 |
After |
35 u + 350 |
7 u + 70 |
4 u + 80 |
28 u + 560 |
Comparing the blue stickers and the green stickers in the end |
35 p |
7 p |
5 p |
35 p |
7 u + 70 = 7 p --- (1)
4 u + 80 = 5 p --- (2)
Make p the same by using the LCM of 5 and 7.
LCM of 5 and 7 is 35.
(1)
x 5 35 u + 350 = 35 p --- (3)
(2)
x 7 28 u + 560 = 35 p --- (4)
(3) = (4)
35 u + 350 = 28 u + 560
35 u - 28 u = 560 - 350
7 u = 210
1 u = 210 ÷ 7 = 30
Number of stickers that Adam has now
= 7 u + 70 + 4 u + 80
= 7 u + 4 u + 70 + 80
= 11 u + 150
= 11 x 30 + 150
= 330 + 150
= 480
Answer(s): 480