| 7 yr ago, the ages of A and B were in the ratio 4: 5 and 7 yr hence, they will be in the ratio 5: 6. The present age of B is |
A) 56 yr
B) 70 yr
C) 63 yr
D) 77 yr
Correct Answer: D
Solution :
| Let present age of A be x yr and present age of B be y yr. |
| According to the question, |
| \[\frac{x-7}{y-7}=\frac{4}{5}\] |
| \[\Rightarrow \] \[5x-35=4y-28\] |
| \[\Rightarrow \] \[5x-4y=7\] (i) |
| and \[\frac{x+7}{y+7}=\frac{5}{6}\] |
| \[\Rightarrow \] \[6x+42=5y+35\] |
| \[\Rightarrow \] \[6x-5y=-7\] (ii) |
| On solving Eqs. (i) and (ii), we get |
| \[y=77\,\,yr\] |
You need to login to perform this action.
You will be redirected in
3 sec
