Surekha travels $10km$ to reach her office she walks $0.5km$ on foot at a speed of $8kmph$ to catch a bus which travels at a speed of $40kmph$ What is the time taken by Surekha to reach the office?

Total distance traveled to reach the office $\left(D\right)=10km$

Let us consider the motion during the walk.

$V=$Speed of Surekha during the walk $=8km/h$

$d=$Distance traveled during walk $=0.5km$

Given that

Let time spent during the walk$=t$

Time spent during the walk, $t=\frac{d}{v}$

$=\frac{0.5}{8}=0.0625hour$

By Bus

Now consider the motion during travel by bus:

$V=$Speed of bus $=40km/h$

$d\text{'}=$ distance remaining to travel to reach office $=D–d=10–0.5=9.5km$

$t\text{'}=$time spent traveling by bus

Time spent traveling by bus $t\text{'}=\frac{d\text{'}}{v}$

$t\text{'}=\frac{9.5}{40}=\frac{95}{10\times 40}$

$t\text{'}=\frac{19}{80}=0.2375hour$

Total time taken to reach the office is given as,

$T=t+t\text{'}$

$T=0.0625+0.2375$

$T=0.3h$

$T=0.3x60minutes=\frac{3}{10}x60minutes=3\times 6minutes=18minutes$

Hence, the time is taken by Surekha to reach the office $=18minutes$.