Question 148128
220=75x+70(3-x)
220=75x+210-70x
220=5x+210
5x=220-210
5x=10
x=10/5
x=2 hours driving @ 75 mph.
3-2=1 hour driving @ 70 mph.
proof
220=75*2=70*1
220=150+70
220=220 
75*2=150 miles from Albuquerque to Roswell.