Question

Tarun can cover a certain distance in $1$ hr $24$ min by covering $\frac{2}{3}$ of the distance at $4$ km/hr and the rest at $5$ km/hr. The total distance is:

• A. $5$ km
• B. $6$ km
• C. $8$ km
• D. $9.2$ km

Answer 1

Answer: (B)

$6$ km

Let the total distance is $x$ km.

Total time=1 hr 24 min=$\frac{21}{15}min$

Tarun covers $\frac{2}{3}$ of the distance at 4 km/hr then time to cover this distance$=\frac{\frac{2}{3s}}{4}$

Remaining distance$=s-\frac{2}{3s}=\frac{1}{3s}$

Tarun covers rest of the distance at 5 km/hr then time to cover rest distance$=\frac{\frac{1}{3s}}{5}$

$\therefore \frac{21}{15}=\frac{2}{12s}+\frac{1}{15s}$

$\Rightarrow \frac{21}{15}=\frac{14}{60s}$

$\Rightarrow s=\frac{14\times 15}{21\times 60}=6km$