Question

Deepa rides her bike at an average speed of $30$ km/hr and reached 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. $54$ minutes
• B. $1$ hour
• C. $40$ minutes
• D. $45$ minutes

Answer 1

The correct option is A $54$ minutes

Average speed of Deepa $=30$ kmph
Time taken to reach the destination $=6$ hours
So, total distance of destination $=6\times 30=180$ km
Time taken to covered $180$ km by Hema $=4$ hours
Speed of Hema $=\frac{180}{4}=45$ kmph
Deepa's new average speed $=30+10=40$ kmph
Time taken $=\frac{180}{40}=4.5$ hrs
Hema's new average speed $=45+5=50$ kmph
Time taken by Hema $=\frac{180}{50}=3.6$ hours
Time difference $=4.5-3.6=0.9$ hours $=0.9\times 60=54$ minutes.