The ratio of the number of red stickers to blue stickers is 7 : 5.
After Adam buys 30 red stickers and 90 blue stickers,
there is an equal number of red stickers and blue stickers.
How many stickers does Adam have now?
|
Red |
Blue |
Before |
7 u |
5 u |
Change |
+ 30 |
+ 90 |
After |
7 u + 30 |
5 u + 90 |
The number of red stickers and blue stickers are equal in the end.
7 u + 30 = 5 u + 90
7 u - 5 u = 90 - 30
2 u = 60
1 u = 60 ÷ 2 = 30
Number of stickers that Adam has now
= 7 u + 30 + 5 u + 90
= 7 u + 5 u + 30 + 90
= 12 u + 120
= 12 x 30 + 120
= 360 + 120
= 480
Answer(s): 480