posted by Kim .
A planehas 7 hrs. to reach a target and come back to base. it flies out to the target at 480 miles per hr. and returns on the same route at 640 miles per hour. how many miles from the base is the target?
let the time for the "out-trip" be t hours
then the return trip took 7-t hours
so first distance = 480t miles
return distance = 640(7-t)miles
but aren't the two distances equal ?
480t = (640(7-t)
then sub your value of t into 480t