Question

A man reaches his office 10 minutes late if he drives his car at 40 kmph, and 5 minutes early if he drives his car at 50 kmph from his home. How should I calculate the distance of his office from his home?

• A. 25
• B. 50
• C. 75
• D. 100

Answer 1

The Correct Option is B

Speed \(=\frac{distance}{time}\) 

40 \(=\frac{distance}{(t+10)}\)

50 \(=\frac{distance}{(t-5)}\) 

\(\frac{4}{5}\) \(=\frac{(t-5)}{(t+10)}\) 

4t + 40 = 5t - 25
t = 65 min
distance = speed \(\times\) time

= 40 \(\times\) \((\frac{75}{60})\) --- in hours
= 50 km
So the correct option is (B)