The ratio of the number of green stickers to red stickers is 3 : 2.
After Adam buys another 10 green stickers and 20 red stickers,
the ratio becomes of the number of green stickers to red stickers is 5 : 4.
How many stickers does Adam have now?
|
Make p the same (1) x 4 = (3) |
(1) Green |
(2) Red |
Make p the same (2) x 5 = (4) |
Before |
12 u |
3 u |
2 u |
10 u |
Change |
+ 40 |
+ 10 |
+ 20 |
+ 100 |
After |
12 u + 40 |
3 u + 10 |
2 u + 20 |
10 u + 100 |
Comparing the green stickers and the red stickers in the end |
20 p |
5 p |
4 p |
20 p |
3 u + 10 = 5 p --- (1)
2 u + 20 = 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 + 40 = 20 p --- (3)
(2)
x 5 10 u + 100 = 20 p --- (4)
(3) = (4)
12 u + 40 = 10 u + 100
12 u - 10 u = 100 - 40
2 u = 60
1 u = 60 ÷ 2 = 30
Number of stickers that Adam has now
= 3 u + 10 + 2 u + 20
= 3 u + 2 u + 10 + 20
= 5 u + 30
= 5 x 30 + 30
= 150 + 30
= 180
Answer(s): 180