The ratio of the number of red stickers to green stickers is 3 : 2.
After Adam buys another 20 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 |
12 u |
3 u |
2 u |
10 u |
Change |
+ 80 |
+ 20 |
+ 50 |
+ 250 |
After |
12 u + 80 |
3 u + 20 |
2 u + 50 |
10 u + 250 |
Comparing the red stickers and the green stickers in the end |
20 p |
5 p |
4 p |
20 p |
3 u + 20 = 5 p --- (1)
2 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 12 u + 80 = 20 p --- (3)
(2)
x 5 10 u + 250 = 20 p --- (4)
(3) = (4)
12 u + 80 = 10 u + 250
12 u - 10 u = 250 - 80
2 u = 170
1 u = 170 ÷ 2 = 85
Number of stickers that Adam has now
= 3 u + 20 + 2 u + 50
= 3 u + 2 u + 20 + 50
= 5 u + 70
= 5 x 85 + 70
= 425 + 70
= 495
Answer(s): 495