A man goes from A to B at a uniform speed of | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(C) Let the distance between $A$ and $B$ be $d \, km$.The time taken to go from $A$ to $B$ is $t_1 = \frac{d}{12} \, h$.The time taken to return from

Vedclass · Accepted Answer

$6$

Vedclass · Answer

(C) Let the distance between $A$ and $B$ be $d \, km$.The time taken to go from $A$ to $B$ is $t_1 = \frac{d}{12} \, h$.The time taken to return from $B$ to $A$ is $t_2 = \frac{d}{4} \, h$.Total distance covered $= d + d = 2d \, km$.Total time taken $= t_1 + t_2 = \frac{d}{12} + \frac{d}{4} = \frac{d + 3d}{12} = \frac{4d}{12} = \frac{d}{3} \, h$.Average speed $= \frac{	ext{Total distance}}{	ext{Total time}} = \frac{2d}{d/3} = 2d 	imes \frac{3}{d} = 6 \, km/h$.Alternatively,for two equal distances covered at speeds $v_1$ and $v_2$,the average speed is $\frac{2v_1v_2}{v_1 + v_2} = \frac{2 	imes 12 	imes 4}{12 + 4} = \frac{96}{16} = 6 \, km/h$.

$A$ man goes from $A$ to $B$ at a uniform speed of $12 \, km/h$ and returns with a uniform speed of $4 \, km/h$. His average speed (in $km/h$) for the whole journey is?

Similar Questions

$A$ car covers the first $39 \, km$ of its journey in $45 \, minutes$ and the remaining $25 \, km$ in $35 \, minutes.$ What is the average speed of the car (in $km/h$)?

$A$ man with $\frac{3}{5}$ of his usual speed reaches the destination $2 \frac{1}{2}$ hours late. Find his usual time to reach the destination? (in $hours$)

Mohan covers $10.2 \, km$ in $3 \, hours$. The distance covered by him in $5 \, hours$ is (in $km$):

The distance between places $A$ and $B$ is $999 \, km$. An express train leaves place $A$ at $6 \, am$ and runs at a speed of $55.5 \, km/h$. The train stops on the way for $1 \, hr \, 20 \, min$. It reaches $B$ at?

$A$ person travels from $P$ to $Q$ at a speed of $40 \, km/hr$ and returns by increasing his speed by $50 \%$. What is his average speed for both the trips? (in $km/hr$)

Vedclass Test Series

Exam Paper Generator

Online Exam Module