The ratio of the number of red stickers to blue stickers is 9 : 7.
After Adam buys 20 red stickers and 80 blue stickers,
there is an equal number of red stickers and blue stickers.
How many stickers does Adam have now?
|
Red |
Blue |
Before |
9 u |
7 u |
Change |
+ 20 |
+ 80 |
After |
9 u + 20 |
7 u + 80 |
The number of red stickers and blue stickers are equal in the end.
9 u + 20 = 7 u + 80
9 u - 7 u = 80 - 20
2 u = 60
1 u = 60 ÷ 2 = 30
Number of stickers that Adam has now
= 9 u + 20 + 7 u + 80
= 9 u + 7 u + 20 + 80
= 16 u + 100
= 16 x 30 + 100
= 480 + 100
= 580
Answer(s): 580