Answer:$6.25
Step-by-step explanation:we have that
x------------------> represent the number of hours Steven babysits
y----------------- > represent the amount he charges
for x=6 hours
y=$37.50 ----------------> y/x=37.5/6=6.25
for x=8 hours
y=$50---------------------> y/x=50/8=6.25
therefore
y=6.25x