The plane will run out of fuel after 10/3 hours.

The distance the plane can cover is the integral from 0 to 10/3 of (6,000,000/(20,000-3,000t)) dt.

= 6,000,000 * -1/3000 * ln(20,000-3,000t) from 10/3 to 0.

= -2,000 * ln(1/2)

= 2000 * ln(2) =~ 1386.3 miles .

Michael Shackleford, A.S.A.