The ratio of the number of red stickers to blue stickers is 7 : 3.
After Adam buys another 20 red stickers and 90 blue stickers,
the ratio becomes of the number of red stickers to blue stickers is 3 : 2.
How many stickers does Adam have now?
|
Make p the same (1) x 2 = (3) |
(1) Red |
(2) Blue |
Make p the same (2) x 3 = (4) |
Before |
14 u |
7 u |
3 u |
9 u |
Change |
+ 40 |
+ 20 |
+ 90 |
+ 270 |
After |
14 u + 40 |
7 u + 20 |
3 u + 90 |
9 u + 270 |
Comparing the red stickers and the blue stickers in the end |
6 p |
3 p |
2 p |
6 p |
7 u + 20 = 3 p --- (1)
3 u + 90 = 2 p --- (2)
Make p the same by using the LCM of 2 and 3.
LCM of 2 and 3 is 6.
(1)
x 2 14 u + 40 = 6 p --- (3)
(2)
x 3 9 u + 270 = 6 p --- (4)
(3) = (4)
14 u + 40 = 9 u + 270
14 u - 9 u = 270 - 40
5 u = 230
1 u = 230 ÷ 5 = 46
Number of stickers that Adam has now
= 7 u + 20 + 3 u + 90
= 7 u + 3 u + 20 + 90
= 10 u + 110
= 10 x 46 + 110
= 460 + 110
= 570
Answer(s): 570