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

[Q]: Problem: the average marks of a class of 40 students is 44 and that of another class of 45 students is 70 . find the average marks of all the students ? 
Options: a ) 52.6 , b ) 52.4 , c ) 52.1 , d ) 69.5 , e ) 52.9
[A]: d


[Q]: Problem: a ’ s speed is 20 / 15 times that of b . if a and b run a race , what part of the length of the race should a give b as a head start , so that the race ends in a dead heat ? 
Options: a ) 1 / 17 , b ) 3 / 17 , c ) 1 / 10 , d ) 5 / 20 , e ) 3 / 10
[A]: d


[Q]: Problem: a clock store sold a certain clock to a collector for 25 percent more than the store had originally paid for the clock . when the collector tried to resell the clock to the store , the store bought it back at 55 percent of what the collector had paid . the shop then sold the clock again at a profit of 70 percent on its buy - back price . if the difference between the clock ' s original cost to the shop and the clock ' s buy - back price was $ 125 , for how much did the shop sell the clock the second time ? 
Options: a ) $ 500 , b ) $ 467.5 , c ) $ 935 , d ) $ 525.5 , e ) $ 465.5
[A]:
b