The ratio of the number of blue stickers to red stickers is 9 : 4.
After Adam buys another 20 blue stickers and 40 red stickers,
the ratio becomes of the number of blue stickers to red stickers is 5 : 3.
How many stickers does Adam have now?
|
Make p the same (1) x 3 = (3) |
(1) Blue |
(2) Red |
Make p the same (2) x 5 = (4) |
Before |
27 u |
9 u |
4 u |
20 u |
Change |
+ 60 |
+ 20 |
+ 40 |
+ 200 |
After |
27 u + 60 |
9 u + 20 |
4 u + 40 |
20 u + 200 |
Comparing the blue stickers and the red stickers in the end |
15 p |
5 p |
3 p |
15 p |
9 u + 20 = 5 p --- (1)
4 u + 40 = 3 p --- (2)
Make p the same by using the LCM of 3 and 5.
LCM of 3 and 5 is 15.
(1)
x 3 27 u + 60 = 15 p --- (3)
(2)
x 5 20 u + 200 = 15 p --- (4)
(3) = (4)
27 u + 60 = 20 u + 200
27 u - 20 u = 200 - 60
7 u = 140
1 u = 140 ÷ 7 = 20
Number of stickers that Adam has now
= 9 u + 20 + 4 u + 40
= 9 u + 4 u + 20 + 40
= 13 u + 60
= 13 x 20 + 60
= 260 + 60
= 320
Answer(s): 320