Question 118717
distance = 42km
time = 28min + 14min = 42min

speed = {{{distance/time}}}

{{{ speed = 42km/42min = 1 (km/min)}}} = 1 km/min

In more usual units of km/hr.
{{{time = 42min (1 hr/60min)}}}= .7 hr

{{{ speed = (42km/.7hr) = 60 (km/hr) }}} = 60 km/hr