The task is to generate the correct answer for a given math problem.

Problem: a solid yellow stripe is to be painted in the middle of a certain highway . if 1 gallon of paint covers an area of w square feet of highway , how many gallons of paint will be needed to paint a stripe of t inches wide on a stretch of highway m miles long ? ( 1 mile = 5,280 feet and 1 foot = 12 inches )
( 5,280 mt ) / 12 w', 'b ) ( 5,280 pt ) / 12 m', 'c ) ( 5,280 pmt ) / 12', 'd ) ( 5,280 ) ( 12 m ) / pt', 'e ) ( 5,280 ) ( 12 p ) / mt'

Problem: a can do a work in 15 days and b in 20 days . if they work on it together for 7 days , then the fraction of the work that is left is
11 / 6

Problem: what is the average ( arithmetic mean ) of the numbers 15 , 16 , 17 , 17 , 18 , and 19 ?
17