Boat speed speed =x mph

current speed =y mph

against current 14 hours

with current 12 hours

Distance against 336 miles distance with 336 miles

t=d/r against current -

336 / ( x - y )= 14

14 ( x - y ) = 336

14 x - 14 y = 336.1

336 / ( x + y )= 12

12 ( x + y ) = 336

12 x + 12 y = 336.2

Multiply (1) by 6

Multiply (2) by 7

we get

84 x + -84 y = 2016

84 x + 84 y = 2352

168 x = 4368

/ 168

x = 26.00 mph

plug value of x in (1) y

14 x -14 y = 336

364 -14 -364 = 336

-14 y = 336

-14 y = -28 mph

y = 2.00

Boat speed speed 26.00 mph

current speed 2.00 mph

It took an avg of 13 mi total 15 mi/hr is the answer for the still water 11 mi/hr is the upstream speed I added 2 and subtracted two because it made sense because there is a difference of two in the hrs it took to go upstream and downstream