Question

A person x sets out awalk from a to b at the same time another person y starts walk from b to a. After passing each other x and y complete journys in 3hours20minuts and 4hours48minuts respectively.If x walk at the speed of 4.5 ,what is the speed of y?Km/hr

Answer 1

We will use the concept of speed as

$v=\frac{d}{t}\\ where\\ d=distance\\ t=time\\v=velocity$

from this relation the distance is related as

$d=vt$

now distance covered by x and distance covered by y is equal

$d_y=d_x$

so from the definition of velocity

$d_{x}=v_x t_x-------(1$

and

$d_{y}=v_y t_y-------(2$

equating the right hand sides of both the equations we get

$v_y t_y=v_x t_x$

from this the speed of y is related as

$v_y=\frac{v_x t_x}{t_y}$

let'c calculate the time into hours first. As 60 minutes means 1 hour so

$t_x=3 h+\frac{20}{60} hr=3h+0.33h=3.33 h$

and

$t_y=4 h+\frac{48}{60} hr=4h+0.8h=4.8 h$

so now using the relation

$v_y=\frac{v_x t_x}{t_y}$

Putting values in we get

$v_y=\frac{3.33\times 4.5}{4.8}$

solving it we get

$v_y=\frac{14.99}{4.8}$

hence speed of y is

$v_y=3.12\: km/h$

------------------------------------------------------------------