The ratio of the number of blue stickers to red stickers is 9 : 7.
After Adam buys 20 blue stickers and 70 red stickers,
there is an equal number of blue stickers and red stickers.
How many stickers does Adam have now?
|
Blue |
Red |
Before |
9 u |
7 u |
Change |
+ 20 |
+ 70 |
After |
9 u + 20 |
7 u + 70 |
The number of blue stickers and red stickers are equal in the end.
9 u + 20 = 7 u + 70
9 u - 7 u = 70 - 20
2 u = 50
1 u = 50 ÷ 2 = 25
Number of stickers that Adam has now
= 9 u + 20 + 7 u + 70
= 9 u + 7 u + 20 + 70
= 16 u + 90
= 16 x 25 + 90
= 400 + 90
= 490
Answer(s): 490