The ratio of the number of blue beads to red beads is 3 : 1. After Henry gives away 20 blue beads and buys another 40 red beads, there is equal number of blue beads and red beads. How many beads does Henry have now?
| |
Blue |
Red |
| Before |
3 u |
1 u |
| Change |
- 20 |
+ 40 |
| After |
3 u - 20 |
1 u + 40 |
The number of blue beads and red beads in the end is the same.
3 u - 20 = 1 u + 40
3 u - 1 u = 40 + 20
2 u = 60
1 u = 60 ÷ 2 = 30
Number of beads that Henry has now
= 3 u - 20 + 1 u + 40
= 3 u + 1 u - 20 + 40
= 4 u + 20
= 4 x 30 + 20
= 120 + 20
= 140
Answer(s): 140
