The ratio of the number of red stickers to blue stickers is 2 : 1.
After Adam buys another 20 red stickers and 90 blue stickers,
the ratio becomes of the number of red stickers to blue stickers is 6 : 5.
How many stickers does Adam have now?
|
Make p the same (1) x 5 = (3) |
(1) Red |
(2) Blue |
Make p the same (2) x 6 = (4) |
Before |
10 u |
2 u |
1 u |
6 u |
Change |
+ 100 |
+ 20 |
+ 90 |
+ 540 |
After |
10 u + 100 |
2 u + 20 |
1 u + 90 |
6 u + 540 |
Comparing the red stickers and the blue stickers in the end |
30 p |
6 p |
5 p |
30 p |
2 u + 20 = 6 p --- (1)
1 u + 90 = 5 p --- (2)
Make p the same by using the LCM of 5 and 6.
LCM of 5 and 6 is 30.
(1)
x 5 10 u + 100 = 30 p --- (3)
(2)
x 6 6 u + 540 = 30 p --- (4)
(3) = (4)
10 u + 100 = 6 u + 540
10 u - 6 u = 540 - 100
4 u = 440
1 u = 440 ÷ 4 = 110
Number of stickers that Adam has now
= 2 u + 20 + 1 u + 90
= 2 u + 1 u + 20 + 90
= 3 u + 110
= 3 x 110 + 110
= 330 + 110
= 440
Answer(s): 440