A deer is standing 60 meters in from the west end of a tunnel. The deer sees a train approaching from the west at a constant speed ten times the speed the deer can run. The deer reacts by running toward the train and clears the exit when the train is 15 meters from the tunnel. If the deer ran in the opposite direction it would barely escape out the eastern entrance just as the train came out of the eastern entrance. How long is the tunnel in meters?  Pick:
A) 125
B) 135
C) 145
D) 155
E) 165
Let x be the length of the tunnel.   When the deer runs 60 meters west, the train goes 600 meters to a point 15 meters from the west entrance of the tunnel.   When the deer runs east, the deer runs x-60 meters while the train goes x + 600 + 15 meters.   x + 600 + 15 = 10(x-60)   9x = 1215   x = 135 meters   The answer is 135.
<result>B</result>
A deer is standing 60 meters in from the west end of a tunnel. The deer sees a train approaching from the west at a constant speed ten times the speed the deer can run. The deer reacts by running toward the train and clears the exit when the train is 15 meters from the tunnel. If the deer ran in the opposite direction it would barely escape out the eastern entrance just as the train came out of the eastern entrance. How long is the tunnel in meters?