The ratio of the number of blue beads to red beads is 9 : 7. After Rael gives away 10 blue beads and buys another 50 red beads, there is equal number of blue beads and red beads. How many beads does Rael have now?
| |
Blue |
Red |
| Before |
9 u |
7 u |
| Change |
- 10 |
+ 50 |
| After |
9 u - 10 |
7 u + 50 |
The number of blue beads and red beads in the end is the same.
9 u - 10 = 7 u + 50
9 u - 7 u = 50 + 10
2 u = 60
1 u = 60 ÷ 2 = 30
Number of beads that Rael has now
= 9 u - 10 + 7 u + 50
= 9 u + 7 u - 10 + 50
= 16 u + 40
= 16 x 30 + 40
= 480 + 40
= 520
Answer(s): 520
