Question

David is rowing a boat upstream. The river is flowing at a speed of 2 miles per hour. David starts rowing at a speed of 6 miles per hour, but as he gets tired his speed decreases (at a rate of 1 mile per hour, every hour). Which equation represents the speed of the boat for x hours spent rowing?

y = 6 − 2x
y = x − 4
y = 4 − x
y = 6 − x
y = x + 4

Answer 1

Y=x - 4 Is Correct. hope This helps

Answer 2

y = 4 - x

Explanation:

Given,

The speed of David's boat = 6 miles per hour,

Speed of stream = 2 miles per hour,

So, the speed of boat in upstream = Speed of boat - Speed of stream

= 6 - 2

= 4 miles per hour,

Now, this speed is decreasing at the rate of 1 miles per hour,

So, the total decreased speed in x hours = x miles per hour,

Hence, the final speed of boat after x hours = ( 4 - x ) miles per hour,

If y represents the final speed ( miles per hour ) of boat after x hours ,

⇒ y = 4 - x

Which is the required equation.