Problema Solution
Two planes leave Los Angeles at the same time. One heads south to San Diego at 80 mph, the other heads north to San Fransico. The San Fransico plane flies 20 miles per hour faster then the San Diego plane. In how many hours will they be 360 miles apart?
Answer provided by our tutors
let
v1 = 80 mph the speed of the planes heading south
v2 = the speed of the plane heading north
d = 360 mi the distance between them
t = the time of the travel
The San Fransico plane flies 20 miles per hour faster then the San Diego plane:
v2 = v1 + 20
v2 = 80 + 20
v2 = 100 mph
since the planes fly in opposite directions the sum of their distances is equal to the distance between them:
v1*t + v2*t = d
80t + 100t = 360
by solving we find:
t = 2 hr
click here to see the step by step solution of the equation:
in 2 hours the planes will be 360 miles apart.