it costs $7 plus $2 for every visit
he wants to spend less than $25 a month
so the inequality would be 7+2V<25
using that equation to find number of visits:
7+2V<25
subtract 7 from both sides
2V<18
divide both sides by 2
v<9
since he has to stay below 9 visits the maximum he can go is 8 times