The ratio of the number of blue stickers to red stickers is 3 : 1.
After Adam buys another 40 blue stickers and 80 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 |
+ 120 |
+ 40 |
+ 80 |
+ 400 |
After |
9 u + 120 |
3 u + 40 |
1 u + 80 |
5 u + 400 |
Comparing the blue stickers and the red stickers in the end |
15 p |
5 p |
3 p |
15 p |
3 u + 40 = 5 p --- (1)
1 u + 80 = 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 + 120 = 15 p --- (3)
(2)
x 5 5 u + 400 = 15 p --- (4)
(3) = (4)
9 u + 120 = 5 u + 400
9 u - 5 u = 400 - 120
4 u = 280
1 u = 280 ÷ 4 = 70
Number of stickers that Adam has now
= 3 u + 40 + 1 u + 80
= 3 u + 1 u + 40 + 80
= 4 u + 120
= 4 x 70 + 120
= 280 + 120
= 400
Answer(s): 400