Question 899642
The snowplow had a two head start and went 2x
The car gained on the plow at (25-x) every hour

x and 25

2x/(25-x)=1/2
4x=25-x
5x=25
x=5 mph 
 let's check
5 mph for the plow
In two hours the plow went 10 miles
The car gains at 25-5=20 mph
10/20=1/2
0k