Question

Meg rowed her boat upstream a distance of 12 mi and then rowed back to the starting point. The total time of the trip was 8 hours. If the rate of the current was 2 mph find the average speed of the boat relative to the water

Answer 1

Answer:

3mph

Step-by-step explanation:

Boat speed x

current speed 2

against current x-2 mph

with current x+ 2 mph

Distance= 5 miles

Time against + time with = 6 hours

5 /( x + 2 ) + 5 /(x - 2 ) = 6

LCD = (x - 2 ) ( x + 2 )

5 *( x - 2 ) + 5 (x + 2 ) = 6

5 x - 10 + 5 x + 10 = 6 ( x ^2 - 4 )

10 x = 6 x ^2 - 24

6 x ^2 - -10 x - 24

Find the roots of the equation by quadratic formula

a= 6 , b= -10 , c= -24

b^2-4ac= 100 + 576

b^2-4ac=676

x1=(10+26)/12

x1=3

x2=(10-26)/12

x2= -1.33

Ignore negative value

Speed of boat is 3 mph