Question 667750
Let him drive x miles at 40 mi/h

he will drive (265-x) miles at 35 mi/h

total time = 7 hours

Time first leg + time second leg = 7

t=d/r
x/40 + (265-x)/35 =7

LCD = 280 
multiply equation by LCD
7x+8(265-x)=7*280

7x+2120-8x=1960

-x= 1960-2120
-x=-160
x= 160 

he travels 160 miles at 40 mi/h