Question

A dolphin starts at an elevation of -16 3/4 feet. He kicks 5 times and increases his elevation by the same amount for each kick. He is now at an elevation of -5 1/4 feet. Which equation can be used to find x, the number of feet the dolphin traveled with each kick?

Answer 1

5x -16 3/4 = -5 1/4

Note: This is based off of Study Island's multiple choice answers

Explanation:

We're trying to figure out how far the dolphin travels with each kick. The dolphin starts at an elevation of -16 3/4 feet and ends up at an elevation of -5 1/4 feet. In other words, what can we add to -16 3/4 to get -5 1/4?

The elevation is our variable (x). The dolphin kicks 5 times to get from point a to point b. So we should add 5x to -16 3/4 to get -5 1/4. This equation will solve for the length in feet traveled per kick. Our equation is now:

5x + -16 3/4 = -5 1/4

Adding a negative is the same thing as subtracting a positive, so our final equation is:

5x - 16 3/4 = -5 1/4

If we want to solve this:

5x - 16.75 = -5.25

5x = 11.5

x = 2.3 feet per kick

Answer 2

`x = 2\,(4)/(5)\,ft`

Explanation:

The equation of elevation for the dolphin is:

`-(67)/(4) + 5\cdot x = -(21)/(4)`

`5\cdot x = (56)/(4)`

`x = 2\,(4)/(5)\,ft`