The ratio of the number of green stickers to blue stickers is 4 : 1.
After Adam buys another 20 green stickers and 50 blue stickers,
the ratio becomes of the number of green stickers to blue stickers is 7 : 4.
How many stickers does Adam have now?
|
Make p the same (1) x 4 = (3) |
(1) Green |
(2) Blue |
Make p the same (2) x 7 = (4) |
Before |
16 u |
4 u |
1 u |
7 u |
Change |
+ 80 |
+ 20 |
+ 50 |
+ 350 |
After |
16 u + 80 |
4 u + 20 |
1 u + 50 |
7 u + 350 |
Comparing the green stickers and the blue stickers in the end |
28 p |
7 p |
4 p |
28 p |
4 u + 20 = 7 p --- (1)
1 u + 50 = 4 p --- (2)
Make p the same by using the LCM of 4 and 7.
LCM of 4 and 7 is 28.
(1)
x 4 16 u + 80 = 28 p --- (3)
(2)
x 7 7 u + 350 = 28 p --- (4)
(3) = (4)
16 u + 80 = 7 u + 350
16 u - 7 u = 350 - 80
9 u = 270
1 u = 270 ÷ 9 = 30
Number of stickers that Adam has now
= 4 u + 20 + 1 u + 50
= 4 u + 1 u + 20 + 50
= 5 u + 70
= 5 x 30 + 70
= 150 + 70
= 220
Answer(s): 220