Question 1055312
Rate * Time = Distance
{{{R[c]*t=100}}}
{{{R[b]*t=40}}}
{{{R[b]=R[c]-30}}}
Substituting,
{{{40/t=100/t-30}}}
{{{-60/t=-30}}}
{{{t=2}}}{{{hr}}}
So then,
{{{R[c]=100/2}}}
{{{R[c]=50}}}{{{mph}}}
{{{R[b]=50-30}}}
{{{R[b]=20}}}{{{mph}}}