Question

What is the greatest possible speed at which a man can walk 52 km and 91 km in an exact number of minutes.

Answer 1

Greatest possible speed = HCF of $(52,91)\Rightarrow$

$2|52$ $7|91$

___________ _____________

$2|26$ $13|13$

___________ ______________

$13|13$ $1$

___________

$1$

So, HCF = $13$ km/hr is the greatest possible speed.