A student traveled 10 percent of the distance of the trip alone, continued another 30 miles with a friend, and then finished the last half of the trip alone. How many miles long was the trip?  Pick one:
A) 75  B) 100  C) 125  D) 150  E) 175
Let x be the total length of the trip.   0.1x + 30 miles + 0.5x = x   30 miles = 0.4x   x = 75 miles   The answer is 75.
<result>A</result>
A student traveled 10 percent of the distance of the trip alone, continued another 30 miles with a friend, and then finished the last half of the trip alone. How many miles long was the trip?