Answer
a. $C=10+0.20(m)$
b. $C=50 dollars$
c. $m=135 minutes$
Work Step by Step
a. $C=cost$
$C=10+0.20(m)$
b. $m=200$
$C=10+0.20(200)$
$C=10+40$
$C=50$
c. $C=37$
$37=10+0.20(m)$
$37-10=0.20(m)$
$27=0.20(m)$
$27\div0.20=m$
$m=135$