The ratio of the number of red stickers to blue stickers is 7 : 2.
After Adam buys another 30 red stickers and 90 blue stickers,
the ratio becomes of the number of red stickers to blue stickers is 8 : 3.
How many stickers does Adam have now?
|
Make p the same (1) x 3 = (3) |
(1) Red |
(2) Blue |
Make p the same (2) x 8 = (4) |
Before |
21 u |
7 u |
2 u |
16 u |
Change |
+ 90 |
+ 30 |
+ 90 |
+ 720 |
After |
21 u + 90 |
7 u + 30 |
2 u + 90 |
16 u + 720 |
Comparing the red stickers and the blue stickers in the end |
24 p |
8 p |
3 p |
24 p |
7 u + 30 = 8 p --- (1)
2 u + 90 = 3 p --- (2)
Make p the same by using the LCM of 3 and 8.
LCM of 3 and 8 is 24.
(1)
x 3 21 u + 90 = 24 p --- (3)
(2)
x 8 16 u + 720 = 24 p --- (4)
(3) = (4)
21 u + 90 = 16 u + 720
21 u - 16 u = 720 - 90
5 u = 630
1 u = 630 ÷ 5 = 126
Number of stickers that Adam has now
= 7 u + 30 + 2 u + 90
= 7 u + 2 u + 30 + 90
= 9 u + 120
= 9 x 126 + 120
= 1134 + 120
= 1254
Answer(s): 1254