Problema Solution
Brian and Jake left there homes, which are 500 miles apart, and drove straight towards each other, it took 4 hours for the two to meet. If jakes speed is 15 mph slower then Brian's, what was Brian's speed?
Answer provided by our tutors
let
v1 = the speed of Jake
v2 = the speed of Brian
t = 4 hr the time
d = 500 mi the distance
since distance = speed*time we have
v1t + v2t = d
t(v1 + v2) = d
4(v1 + v2) = 500 divide both sides by 4
v1 + v2 = 125
Jake's speed is 15 mph slower then Brian's:
v1 = v2 - 15
by solving the system of equations:
v1 + v2 = 125
v1 = v2 - 15
we find:
v1 = 55 mph
v2 = 70 mph
click here to see the step by step solution of the system of equations:
Brian's speed is 70 mph.