Subject: General Aptitude · Chapter: Time and Distance · Exam: · Marks: · Difficulty:
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 minutes
(b)45 minutes
(c)54 minutes
(d)1 hour
(e)None of these
Answer
Answer (as printed): C
Explanation
Deepa's original speed = 30 km/hr. Deepa's new speed $=(30+10) \mathrm{km} / \mathrm{hr}=40 \mathrm{km} / \mathrm{hr}$. Distance $=(30 \times 6) \mathrm{km}=180 \mathrm{km}$. Hema's original speed $=\left(\frac{180}{4}\right) \mathrm{km} / \mathrm{hr}=45 \mathrm{km} / \mathrm{hr}$. Hema's new speed $=(45+5) \mathrm{km} / \mathrm{hr}=50 \mathrm{km} / \mathrm{hr}$. Difference in time $$=\left(\frac{180}{40}-\frac{180}{50}\right) \mathrm{hrs}=\frac{9}{10} \mathrm{hrs}=\left(\frac{9}{10} \times 60\right) \mathrm{min}=54 \mathrm{min} .$$