You can look at it as a equation of cost. Let’s assume that X is the distance where both cars have the same costs
For Honda is then $15 + $0.15x
For Ford is then $25 + $0.25x
Let’s compare these distances
$15 + $0.15x = $25 + $0.25x
This gives us $0.25x = $10
So x = 40 miles
Honda is cheaper up maximum 40 miles driven. Then Ford becomes cheaper.