Let's come up with variables to substitute and make an equation.
T = total number of minutes
P = number of minutes used by each person in the phone plan
R = remaining minutes per month
R=T-3P
Now that we have an equation, we can substitute the numbers we are given in the problem to find the final solution.
R= 675- 3(250)
R= 675- 750
R= -75 minutes
There are no remaining minutes, and in fact, the people on the phone plan have used 75 extra minutes than provided for in their phone plan.