Question

A man starts from L to M, another from M to L at the same time. After passing each other, they complete their journey in $3\frac{1}{3}and4\frac{4}{5}hr$ respectively. Find the speed of the second man if the speed of the first is 24km/hr

• A. undefined
• B. undefined
• C. undefined
• D. undefined

Answer 1

Let A be the man going from L to M
B be the man going from M to L
Let the point at which they meet be at n km, From L
$\therefore$ Time at which they meet $\frac{xkm}{24km/hr}\to$ speed of A
$=\frac{x}{24}hrs$
$\therefore$ To cover distance of (d - x) k takes $3\frac{1}{3}hr=\frac{10}{3}hr$
Which means $(d-n)=\frac{10}{3}hr\times \frac{24km}{100}=\frac{240}{3}=80km$
$\Rightarrow$ B has taken $\frac{x}{24}$km to travel 80km.
Hence speed of $B=\frac{80}{\frac{x}{24}}=\frac{80\times 24}{n}km/hr$ - (1)
& B takes $4\frac{4}{5}hr$ to travel x km
$\therefore SpeedodB=\frac{x}{4415}=\frac{5x}{24}km/hr$ - (2)
Equating (1) & (2)
$\frac{80\times 24}{x}=\frac{5x}{24}=x^2=\frac{\text{/}{80}^{16}\times 24\times 24}{\text{/}5}x=\sqrt{16\times {24}^2}=4\times 44=96km\therefore SpeedofB=\frac{5\times \text{/}{96}^4}{\text{/}24}=20km/hr$