Train X and train Y pass one another traveling in opposite directions. Thirty minutes later they are 100 miles apart. If train X’s constant speed is 40 miles per hour greater than train Y’s, how far does train X travel during that time?	Choose one:
A) 28 B) 40 C) 60 D) 72 E) 80
Let the rate of the Train Y be R   Then the rate of the Train X will be R+40 (given)   As per relative rate concept, the rate at which they are increasing the distance between them is R+(R+40) [add the rates] i.e. 2R+40   d=100 and t = 30 min i.e 30/60 hr   using RTD table, (2R+40) * 30/60 = 100 ==&gt; R= 80 miles/hr   So the rate of train X is 120 miles/hr (since R+40)   The distance traveled by Train X in 30 min is R*T = 120 * 30/60= 
<gadget id="calculator">120 * 30/60</gadget>
<output>60</output>
60 miles (60)
<result>C</result>
Train X and train Y pass one another traveling in opposite directions. Thirty minutes later they are 100 miles apart. If train X’s constant speed is 40 miles per hour greater than train Y’s, how far does train X travel during that time?