Question 902573
Trick 1:
{{{Speed=Distance/Time}}}
{{{40=15/Time}}}
{{{Time=15/40}}}
{{{Time=0.375}}} km per hour


Trick 2:
1 hour --> 40 km
? hour --> 15 km
{{{Time=(1*15)/40}}}
{{{Time=15/40}}}
{{{Time=0.375}}} km per hour