The ratio of the number of blue stickers to red stickers is 3 : 1.
After Adam buys another 20 blue stickers and 60 red stickers,
the ratio becomes of the number of blue stickers to red stickers is 5 : 3.
How many stickers does Adam have now?
|
Make p the same (1) x 3 = (3) |
(1) Blue |
(2) Red |
Make p the same (2) x 5 = (4) |
Before |
9 u |
3 u |
1 u |
5 u |
Change |
+ 60 |
+ 20 |
+ 60 |
+ 300 |
After |
9 u + 60 |
3 u + 20 |
1 u + 60 |
5 u + 300 |
Comparing the blue stickers and the red stickers in the end |
15 p |
5 p |
3 p |
15 p |
3 u + 20 = 5 p --- (1)
1 u + 60 = 3 p --- (2)
Make p the same by using the LCM of 3 and 5.
LCM of 3 and 5 is 15.
(1)
x 3 9 u + 60 = 15 p --- (3)
(2)
x 5 5 u + 300 = 15 p --- (4)
(3) = (4)
9 u + 60 = 5 u + 300
9 u - 5 u = 300 - 60
4 u = 240
1 u = 240 ÷ 4 = 60
Number of stickers that Adam has now
= 3 u + 20 + 1 u + 60
= 3 u + 1 u + 20 + 60
= 4 u + 80
= 4 x 60 + 80
= 240 + 80
= 320
Answer(s): 320