In this task, you need to answer the given multiple-choice question on the physics. Classify your answers into 'a', 'b', 'c', 'd', and 'e'.

[EX Q]: Problem: train a leaves the station traveling at 30 miles per hour . two hours later train leaves the same station traveling in the same direction at 36 miles per hour . how many miles from the station was train a overtaken by train b ?
Options: a ) 320 , b ) 360 , c ) 400 , d ) 440 , e ) 480
[EX A]: b

[EX Q]: Problem: 82 a 7 + 6 b ____ 190 if a and b represent positive single digits in the correctly worked computation above , what is the value of a + 2 b ?
Options: a ) 2 , b ) 6 , c ) 9 , d ) 11 , e ) 12
[EX A]: b

[EX Q]: Problem: a vessel of capacity 75 litres is fully filled with pure milk . nine litres of milk is removed from the vessel and replaced with water . nine litres of the solution thus formed is removed and replaced with water . find the quantity of pure milk in the final milk solution ?
Options: a ) 23.89 , b ) 72.9 , c ) 58.08 , d ) 78.3 , e ) 79.3
[EX A]:
c