The ratio of the number of red stickers to green stickers is 2 : 1.
After Adam buys another 40 red stickers and 50 green stickers,
the ratio becomes of the number of red stickers to green stickers is 5 : 4.
How many stickers does Adam have now?
|
Make p the same (1) x 4 = (3) |
(1) Red |
(2) Green |
Make p the same (2) x 5 = (4) |
Before |
8 u |
2 u |
1 u |
5 u |
Change |
+ 160 |
+ 40 |
+ 50 |
+ 250 |
After |
8 u + 160 |
2 u + 40 |
1 u + 50 |
5 u + 250 |
Comparing the red stickers and the green stickers in the end |
20 p |
5 p |
4 p |
20 p |
2 u + 40 = 5 p --- (1)
1 u + 50 = 4 p --- (2)
Make p the same by using the LCM of 4 and 5.
LCM of 4 and 5 is 20.
(1)
x 4 8 u + 160 = 20 p --- (3)
(2)
x 5 5 u + 250 = 20 p --- (4)
(3) = (4)
8 u + 160 = 5 u + 250
8 u - 5 u = 250 - 160
3 u = 90
1 u = 90 ÷ 3 = 30
Number of stickers that Adam has now
= 2 u + 40 + 1 u + 50
= 2 u + 1 u + 40 + 50
= 3 u + 90
= 3 x 30 + 90
= 90 + 90
= 180
Answer(s): 180