The ratio of the number of red stickers to blue stickers is 9 : 4.
After Adam buys another 60 red stickers and 70 blue stickers,
the ratio becomes of the number of red stickers to blue stickers is 8 : 5.
How many stickers does Adam have now?
|
Make p the same (1) x 5 = (3) |
(1) Red |
(2) Blue |
Make p the same (2) x 8 = (4) |
Before |
45 u |
9 u |
4 u |
32 u |
Change |
+ 300 |
+ 60 |
+ 70 |
+ 560 |
After |
45 u + 300 |
9 u + 60 |
4 u + 70 |
32 u + 560 |
Comparing the red stickers and the blue stickers in the end |
40 p |
8 p |
5 p |
40 p |
9 u + 60 = 8 p --- (1)
4 u + 70 = 5 p --- (2)
Make p the same by using the LCM of 5 and 8.
LCM of 5 and 8 is 40.
(1)
x 5 45 u + 300 = 40 p --- (3)
(2)
x 8 32 u + 560 = 40 p --- (4)
(3) = (4)
45 u + 300 = 32 u + 560
45 u - 32 u = 560 - 300
13 u = 260
1 u = 260 ÷ 13 = 20
Number of stickers that Adam has now
= 9 u + 60 + 4 u + 70
= 9 u + 4 u + 60 + 70
= 13 u + 130
= 13 x 20 + 130
= 260 + 130
= 390
Answer(s): 390