Question

A dolphin swims 665,280 feet in 3 hours. Use the formula d = rt, where d represents distance, r represents rate, and t represents time, to answer the following questions. Show your work.

Answer 1

Part A: Rearrange the distance formula, d = rt, to solve for rate. (2 points)

Part B: Find the dolphin's rate in feet per hour. (3 points)

Part C: Find the dolphin's rate in miles per hour. (3 points)

Part D: Which unit, feet, or miles, makes more sense to use in this scenario, and why? (2 points)

Answer 2

Part A: it wants you to solve for r. we can do this by isolating r such that r is by itself on one side of the equation. notice how r is being multiplied by t, so you can divide both sides by t to get r by itself

part B: once you have your formula for r from the previous step, plug in d = 665,280 feet and t = 3 hours and evaluate r. notice the units - r will be in feet/hr based on the units of d and t.

part C: 1 mile = 5280 feet. so you can take the rate from part B and divide it by 5280 to convert feet to miles.

part D: compare your rates from part B + C. as a general rule, we try to pick units to avoid quantities that are excessively large or excessively small (ex: you would measure the size of an atom in something small like nm or angstroms, rather than meters). with that in mind, which do you think is a more reasonable way to express the dolphin's speed?