Question 800991
Departs (GMT) 29/8 23:30 +8:00 = 30/8 07:30
Duration: 6250/15 = 416.66 hrs = 416/24 days + 40 min = 17 days 8 hrs 40 min
Expected arrival (GMT) 17/9 16:10
(LT) 18/9 00:10

Remaining distance = 6250 - 3330 = 2920 miles

speed=distance/time so time= distance/speed
original 2920/15
new 2920/S
{{{ 2920/15 - 36 = 2920/S }}}
{{{ (2920-15*36)/15 = 2920/S }}}
{{{ S = 2920/(2920-540)*15 = 18.4}}}
New speed is 18.4 kt