The ratio of the number of green stickers to red stickers is 5 : 3.
After Adam buys another 60 green stickers and 90 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 |
20 u |
5 u |
3 u |
15 u |
Change |
+ 240 |
+ 60 |
+ 90 |
+ 450 |
After |
20 u + 240 |
5 u + 60 |
3 u + 90 |
15 u + 450 |
Comparing the green stickers and the red stickers in the end |
20 p |
5 p |
4 p |
20 p |
5 u + 60 = 5 p --- (1)
3 u + 90 = 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 20 u + 240 = 20 p --- (3)
(2)
x 5 15 u + 450 = 20 p --- (4)
(3) = (4)
20 u + 240 = 15 u + 450
20 u - 15 u = 450 - 240
5 u = 210
1 u = 210 ÷ 5 = 42
Number of stickers that Adam has now
= 5 u + 60 + 3 u + 90
= 5 u + 3 u + 60 + 90
= 8 u + 150
= 8 x 42 + 150
= 336 + 150
= 486
Answer(s): 486