Answer
Let $m$ = the number of months when membership cost the same.
$25m+125=30m+50$
15 months
Work Step by Step
$25m+125=30m+50$
Subtract $50$ from both sides.
$25m+75=30m$
Subtract $25m$ from both sides
$75=5m$
To solve for the variable, divide each side by 5.
$15=m$ or $m=15$