Question

a boat 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?

Answer 1

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

Answer 2

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