You can
put this solution on YOUR website! .
Let x be the Brett' speed.
Then you have this equation
4x = 4*30 + 80
saying that in 4 hours traveled time Brett covered the distance of 4x miles, while Julie covered 4*30 miles
and Brett's distance was 80 miles longer then that of Julie.
From the equation,
4x = 120 + 80 = 200,
x = 200/4 = 50 miles per hour. ANSWER
Solved.