So use pythagorean theorem to find the straight distance between hhouses
legs are 6 and 8
a^2+b^2=c^2
6^2+8^2=c^2
36+64=c^2
100=c^2
squrer root both sides
10=c
the distance=10 miles
To help you with it, plug-in 15 in each equation and see what you get!
Can you add the price of the tickets?