The ratio of the number of blue buttons to red buttons is 3 : 1. After Vaidev gives away 60 blue buttons and buys another 90 red buttons, there is equal number of blue buttons and red buttons. How many buttons does Vaidev have now?
| |
Blue |
Red |
| Before |
3 u |
1 u |
| Change |
- 60 |
+ 90 |
| After |
3 u - 60 |
1 u + 90 |
The number of blue buttons and red buttons in the end is the same.
3 u - 60 = 1 u + 90
3 u - 1 u = 90 + 60
2 u = 150
1 u = 150 ÷ 2 = 75
Number of buttons that Vaidev has now
= 3 u - 60 + 1 u + 90
= 3 u + 1 u - 60 + 90
= 4 u + 30
= 4 x 75 + 30
= 300 + 30
= 330
Answer(s): 330
