Aptitude Discussion

Q. |
By walking at (dfrac{3}{4}^{th}) of his usual speed, a man reaches office 20 minutes later than usual. What is his usual time? |

✖ A. |
30 min |

✔ B. |
60 min |

✖ C. |
70 min |

✖ D. |
50 min |

**Solution:**

Option(**B**) is correct

\(\dfrac{3}{4}\) of a man's usual speed means, he takes \(\dfrac{4}{3}\) of his usual time to cover the same distance, i.e. he takes

\(=\dfrac{4}{3}-1\)

\(=\dfrac{1}{3}\) time extra.

\(\dfrac{1}{3}\) time is 20 minutes (given)

Usual time = $20\times 3$= **60 minutes**