The ratio of the number of red stickers to blue stickers is 7 : 4.
After Adam buys another 70 red stickers and 80 blue stickers,
the ratio becomes of the number of red stickers to blue stickers is 7 : 6.
How many stickers does Adam have now?
|
Make p the same (1) x 6 = (3) |
(1) Red |
(2) Blue |
Make p the same (2) x 7 = (4) |
Before |
42 u |
7 u |
4 u |
28 u |
Change |
+ 420 |
+ 70 |
+ 80 |
+ 560 |
After |
42 u + 420 |
7 u + 70 |
4 u + 80 |
28 u + 560 |
Comparing the red stickers and the blue stickers in the end |
42 p |
7 p |
6 p |
42 p |
7 u + 70 = 7 p --- (1)
4 u + 80 = 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 42 u + 420 = 42 p --- (3)
(2)
x 7 28 u + 560 = 42 p --- (4)
(3) = (4)
42 u + 420 = 28 u + 560
42 u - 28 u = 560 - 420
14 u = 140
1 u = 140 ÷ 14 = 10
Number of stickers that Adam has now
= 7 u + 70 + 4 u + 80
= 7 u + 4 u + 70 + 80
= 11 u + 150
= 11 x 10 + 150
= 110 + 150
= 260
Answer(s): 260