Question

The table below represents the displacement of a turtle from its nest as a function of time: Time (hours) x Displacement from nest (miles) y 0 5 1 27 2 49 3 71 4 93 Part A: What is the y-intercept of the function, and what does this tell you about the turtle? (4 points) Part B: Calculate the average rate of change of the function represented by the table between x = 1 to x = 4 hours, and tell what the average rate represents. (4 points) Part C: What would be the domain of the function if the turtle continued to walk at this rate until it traveled 225 miles from the nest? (2 points) (10 points)

Answer 1

Part A: The y-intercept is 5. If you look to the data, when x=0, y=5. This means that the turtle started off 5 miles away from its nest. (at 0 hours, the distance away from his nest was 5 miles)

Part B:Answer=22. Remember, if you take any two distinct points on a line, the slope of the line will be equal to the average rate of change. In short,  we're just looking for the slope between the ordered pairs (1,27) and (4,93). The formula for slope is:

$slope= \frac{y_{2}- y_{1} }{ x_{2} - x_{1} } = \frac{93-27}{4-1}= \frac{66}{3}=22$

The average rate of change between x=1 and x=4 is 22. The average rate of changed describes the rate at which miles is changing with respect the the change in hour.

Part C: Answer=10hours. Since by now we know both the slope and the y-intercept, lets write the equation in slope intercept form and then solve for 225 miles.

y=mx+b
y=22x+5
225=22x+5
subtract 5 from both sides
220=22x
divide both sides by 22
10=x
It would take 10 hours for the turtle to travel 225miles from it's nest.