Question

A car takes $4$ hours to reach the destination by travelling at a speed of $60$ km/h. How long will it take if the car travels at a speed of $80$ km/h.

Answer 1

As speed increases, time taken decreases in same proportion. So the time taken and varies inversely to the speed of the vehicle for the same distance.

$\frac{60}{80}=\frac{x}{4}$ $60\times x=80$ and $4÷x=y$

$60\times 4=80\times x$ $x=\frac{80}{60}$

$x=\frac{60\times 4}{80}=3$ hr $4÷\frac{80}{60}=y$

$y=\frac{4\times 60}{80}=3$ hr