Question

Walking at 5/7th of your usual speed, you will reach the school 16min late. What is the usual time taken by you to reach your school?

• A. 20min
• B. 40min
• C. 80min
• D. 30min

Answer 1

The correct option is B

40min

We know that Speed = $\frac{Distance}{Time}$

or, Distance = $Speed\times Time$

Here, distance travelled is same (from your home to school), So, More the speed, less the time is taken (speed and time have an inverse relation if the distance of travel is same).

So, here, usually, D = $S\times T$

Also, D = $\frac{5}{7}\times S\times T^{\prime }$, ( where T' = T+16, late by 16min)

So, D = $S\times T=\frac{5}{7}\times S\times (T+16)$

7T = 5T + 80

On solving we'll get, T = 40min