The ratio of the number of red stickers to blue stickers is 4 : 3.
After Adam buys another 20 red stickers and 50 blue stickers,
the ratio becomes of the number of red stickers to blue stickers is 8 : 7.
How many stickers does Adam have now?
|
Make p the same (1) x 7 = (3) |
(1) Red |
(2) Blue |
Make p the same (2) x 8 = (4) |
Before |
28 u |
4 u |
3 u |
24 u |
Change |
+ 140 |
+ 20 |
+ 50 |
+ 400 |
After |
28 u + 140 |
4 u + 20 |
3 u + 50 |
24 u + 400 |
Comparing the red stickers and the blue stickers in the end |
56 p |
8 p |
7 p |
56 p |
4 u + 20 = 8 p --- (1)
3 u + 50 = 7 p --- (2)
Make p the same by using the LCM of 7 and 8.
LCM of 7 and 8 is 56.
(1)
x 7 28 u + 140 = 56 p --- (3)
(2)
x 8 24 u + 400 = 56 p --- (4)
(3) = (4)
28 u + 140 = 24 u + 400
28 u - 24 u = 400 - 140
4 u = 260
1 u = 260 ÷ 4 = 65
Number of stickers that Adam has now
= 4 u + 20 + 3 u + 50
= 4 u + 3 u + 20 + 50
= 7 u + 70
= 7 x 65 + 70
= 455 + 70
= 525
Answer(s): 525