The ratio of the number of blue stickers to red stickers is 2 : 1.
After Adam buys another 20 blue stickers and 40 red stickers,
the ratio becomes of the number of blue stickers to red stickers is 7 : 6.
How many stickers does Adam have now?
|
Make p the same (1) x 6 = (3) |
(1) Blue |
(2) Red |
Make p the same (2) x 7 = (4) |
Before |
12 u |
2 u |
1 u |
7 u |
Change |
+ 120 |
+ 20 |
+ 40 |
+ 280 |
After |
12 u + 120 |
2 u + 20 |
1 u + 40 |
7 u + 280 |
Comparing the blue stickers and the red stickers in the end |
42 p |
7 p |
6 p |
42 p |
2 u + 20 = 7 p --- (1)
1 u + 40 = 6 p --- (2)
Make p the same by using the LCM of 6 and 7.
LCM of 6 and 7 is 42.
(1)
x 6 12 u + 120 = 42 p --- (3)
(2)
x 7 7 u + 280 = 42 p --- (4)
(3) = (4)
12 u + 120 = 7 u + 280
12 u - 7 u = 280 - 120
5 u = 160
1 u = 160 ÷ 5 = 32
Number of stickers that Adam has now
= 2 u + 20 + 1 u + 40
= 2 u + 1 u + 20 + 40
= 3 u + 60
= 3 x 32 + 60
= 96 + 60
= 156
Answer(s): 156