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'.

Problem: a car travels uphill at 30 km / hr and downhill at 90 km / hr . it goes 100 km uphill and 50 km downhill . find the average speed of the car ? 
Options: a ) 32 kmph , b ) 39 kmph , c ) 34 kmph , d ) 35 kmph , e ) 36 kmph
b

Problem: caleb spends $ 64.50 on 50 hamburgers for the marching band . if single burgers cost $ 1.00 each and double burgers cost $ 1.50 each , how many double burgers did he buy ? 
Options: a ) 29 , b ) 10 , c ) 20 , d ) 40 , e ) 45
a

Problem: what is the range of all the roots of | x ^ 2 - 4 | = x ? 
Options: a ) 4 , b ) 3 , c ) 2 , d ) 1 , e ) 0

b