Solution
Miguel and 3 of his friends went to the movies.
They originally had a total of $40.00.
Since each boy have the same amount, let the amount each boy have left after the ticket be m
The amount each boy have left is

Each boy spent $7.50 on a ticket, i.e

The amount of money that each boy have left can be expressed as

Solving for m

Hence, each boy have $2.5 left after buying his ticket.