A man cycles at the speed of 8 km/hr and reaches office at 11 am and when he cycles at the speed of 12 km/hr, he reaches office at 9 am. At what speed should he cycle so that he reaches his office at 10 am ?
A. 9.6 km/hrs
B. 10 km/hrs
C. 11.2 km/hrs
D. Cannot be determined
Answer: Option A
Solution(By Examveda Team)
First speed = 8 km/hrSecond speed = 12 km/hr
Starting time will be same in both conditions.
Distance travelled by first speed in 2 hours
Time take by second speed to travel distance 16 km
$$\eqalign{ & {\text{Time}} = \frac{{{\text{Distance }}}}{{{2^{{\text{nd}}}}{\text{Speed }} - {\text{ }}{{\text{1}}^{{\text{st}}}}{\text{Speed}}}} \cr & {\text{Time}} = \frac{{16}}{{12 - 8}} \cr & {\text{Time}} = 4{\text{ hrs}} \cr} $$
Total time taken by second speed = 4 hrs
Total distance = 4 × 12 = 48 km
Starting time to travel at second speed :
= 9 am - 4 hrs = 5 am
Total time taken by third speed to reach the office :
= 10 am - 5 am = 5 hrs
$$\eqalign{ & {{\text{3}}^{{\text{rd}}}}{\text{ Speed}} = \frac{{{\text{Total Distance}}}}{{{\text{Time}}}} \cr & {{\text{3}}^{{\text{rd}}}}{\text{ Speed}} = \frac{{48}}{5} \cr & {{\text{3}}^{{\text{rd}}}}{\text{ Speed}} = 9.6{\text{ km/hrs}} \cr} $$
Related Questions on Speed Time and Distance
A. 48 min.
B. 60 min.
C. 42 min.
D. 62 min.
E. 66 min.
A. 262.4 km
B. 260 km
C. 283.33 km
D. 275 km
E. None of these
A. 4 hours
B. 4 hours 30 min.
C. 4 hours 45 min.
D. 5 hours
Join The Discussion