The ratio of the number of blue stickers to red stickers is 3 : 2.
After Adam buys another 50 blue stickers and 80 red stickers,
the ratio becomes of the number of blue stickers to red stickers is 8 : 7.
How many stickers does Adam have now?
|
Make p the same (1) x 7 = (3) |
(1) Blue |
(2) Red |
Make p the same (2) x 8 = (4) |
Before |
21 u |
3 u |
2 u |
16 u |
Change |
+ 350 |
+ 50 |
+ 80 |
+ 640 |
After |
21 u + 350 |
3 u + 50 |
2 u + 80 |
16 u + 640 |
Comparing the blue stickers and the red stickers in the end |
56 p |
8 p |
7 p |
56 p |
3 u + 50 = 8 p --- (1)
2 u + 80 = 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 21 u + 350 = 56 p --- (3)
(2)
x 8 16 u + 640 = 56 p --- (4)
(3) = (4)
21 u + 350 = 16 u + 640
21 u - 16 u = 640 - 350
5 u = 290
1 u = 290 ÷ 5 = 58
Number of stickers that Adam has now
= 3 u + 50 + 2 u + 80
= 3 u + 2 u + 50 + 80
= 5 u + 130
= 5 x 58 + 130
= 290 + 130
= 420
Answer(s): 420