Question

Two bicycle riders, Jeff and Nancy, are 25 miles apart, riding toward each other at speeds of 15 mph and 10 mph, respectively. A fly starts from Jeff and flies toward Nancy and then back to Jeff again and so on. The fly continues flying back and forth at a constant rate of 40 mph, until the bicycle riders "collide" and crush the fly. How far has the fly traveled?

Answer 1

it takes the riders one hour to "collide"

the fly is flying at 40 miles per hour