The average cost for a single user unlimited cell phone plan is 75$, $82.50 $78.75 or $80

The average cost is $80

The average cost is $79.06 because if we take 75+82.50+78.75+80, we get 316.25. We must then divide this number by the amount of plans. 316.25/4=$79.0625

We must then round to the nearest hundredth, because money goes to the hundredths place. We round down to get $79.06.