A boat traveled 240 miles downstream and back. The trip downstream took 12 hours. The trip back took 24 hours. What is the speed

Question

3 years ago

12

of the boat in still water? What is the speed of the current?

1 answer:

RoseWind [281] · Answer 1 · 2022-12-01T18:44:57+03:00

Answer:

rate boat = 15 mph

rate current = 5 mph

explanation:

d = r * t

t = d/r

240 / (r_boat + current) = 12 Multiply both sides by r_boat + r_current.

240 = 12(r_boat + current)

240/ (r_boat - current) = 24 Multiply both sides by r_boat - r_current

240 = 24*(r_boat - current)

Since the distances are the same in both equations, you can equate the right side of each.

12 (r_boat + current) = 24(r_boat - current) Divide by 12

r_boat + current = 2 (r_boat - current) Remove the brackets.

r_boat + current = 2*r_boat - 2* current add 2 currents to both sides

r_boat + 3currents = 2*r_boat Subtract r_boat both sides

3 currents = r_boat.

240 = 12*(r_boat + current. Divide by 12

20 = r_boat + current Put 3 currents in for r_boat

20 = 3currents + 1 current Combine

20 = 4 currents Divide by 4

5 = current

The rate of the current = 5 miles / hour

3 currents = r_boat

3*5 = rate_boat

15 = rate of the boat