Deepa rides her bike at an average speed of 30 km/hr and reaches her destination in 6 hours. Hema covers the same distance in 4 hours. If Deepa increases her average speed by 10 km/hr and Hema increases her average speed by 5 km/hr, what would be the difference in their time taken to reach the destination ?

A. 40 min

B. 45 min

C. 54 min

D. 1 hr

E. None of these

Answer: Option C

Solution(By Examveda Team)

Deepa's original speed = 30 km/hr
Deepa's new speed :
= (30 + 10) km/hr = 40 km/hr
Distance = (30 × 6) km = 180 km
Hema's original speed :
= $$\frac{180}{4}$$ km/hr = 45 km/hr
Hema's new speed :
= (45 + 5) km/hr = 50 km/hr
Difference in time :
$$\eqalign{ & = \left( {\frac{{180}}{{40}} - \frac{{180}}{{50}}} \right){\text{ hrs}} \cr & = \frac{9}{{10}}{\text{ hrs}} \cr & = \left( {\frac{9}{{10}} \times 60} \right){\text{ min}} \cr & = 54{\text{ min}} \cr} $$