The ratio of the number of red stickers to green stickers is 8 : 5.
After Adam buys another 20 red stickers and 30 green stickers,
the ratio becomes of the number of red stickers to green stickers is 4 : 3.
How many stickers does Adam have now?
|
Make p the same (1) x 3 = (3) |
(1) Red |
(2) Green |
Make p the same (2) x 4 = (4) |
Before |
24 u |
8 u |
5 u |
20 u |
Change |
+ 60 |
+ 20 |
+ 30 |
+ 120 |
After |
24 u + 60 |
8 u + 20 |
5 u + 30 |
20 u + 120 |
Comparing the red stickers and the green stickers in the end |
12 p |
4 p |
3 p |
12 p |
8 u + 20 = 4 p --- (1)
5 u + 30 = 3 p --- (2)
Make p the same by using the LCM of 3 and 4.
LCM of 3 and 4 is 12.
(1)
x 3 24 u + 60 = 12 p --- (3)
(2)
x 4 20 u + 120 = 12 p --- (4)
(3) = (4)
24 u + 60 = 20 u + 120
24 u - 20 u = 120 - 60
4 u = 60
1 u = 60 ÷ 4 = 15
Number of stickers that Adam has now
= 8 u + 20 + 5 u + 30
= 8 u + 5 u + 20 + 30
= 13 u + 50
= 13 x 15 + 50
= 195 + 50
= 245
Answer(s): 245