Aboat traveled 336 miles downstream and back. the trip downstream took 12 hours. the trip back took 14 hours. what is the speed of the boat in still water? what is the speed of the. current?

Boat speedspeed=xmph
current speed=ymph
against current 14hours
withcurrent 12hours

Distance against 336milesdistance with 336miles
t=d/ragainstcurrent -
336/(x-y)=14
14(x-y)=336
14x-14y=3361

336/(x+y)=12
12(x+y)=336
12x+12y=3362
Multiply (1) by6 
Multiply (2) by7

we get
84x+-84y=2016
84x+84y=2352
168x=4368
/168
x=26.00mph

plug value of x in (1)y
14x-14y=336
364-14-364=336
-14y=336
-14y=-28mph
y=2.00
Boat speedspeed26.00mph
current speed2.00mph 

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