Day 17, they will have the same amount of money.
$92 - ($5 • 17) = 7
$41 - ($2 • 17) = 7
Let 17 represent the amount of days they both spent money, AND the day they ended up with the same amount of money. No other day before 17, they would’ve had the same amount of money. You can figure this out by plugging a different number in for 17, and seeing the answer will not be the same for both equations
Hope this helps.