TASK DEFINITION: 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: Problem: working simultaneously and independently at an identical constant rate , 5 machines of a certain type can produce a total of x units of product p in 4 days . how many of these machines , working simultaneously and independently at this constant rate , can produce a total of 2 x units of product p in 2 days ? 
Options: a ) 11 , b ) 13 , c ) 15 , d ) 18 , e ) 20

SOLUTION: e

PROBLEM: Problem: what is the next number : 2 , 17 , 257 , __ 
Options: a ) 2977 , b ) 3837 , c ) 4097 , d ) 4847 , e ) 5387

SOLUTION: c

PROBLEM: Problem: find 60 / 42 * 4 
Options: a ) 14.7653 , b ) 0.5897 , c ) 3.6974 , d ) 0.3571 , e ) 1.2587

SOLUTION:
d