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.

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 1

Answers:

• A) r = d/t
• B) 221,760 feet per hour
• C) 42 miles per hour
• D) Miles makes more sense

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Work Shown:

Part A

d = r*t

d/t = r*t/t ...... dividing both sides by t

d/t = r

r = d/t

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Part B

Plug in the distance d = 665,280 feet and the time t = 3 hours

You should get the following

r = d/t

r = (665,280 feet)/(3 hours)

r = 221,760 feet per hour

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Part C

Divide by 5280 to convert from feet to miles.

This works because 5280 feet = 1 mile

665,280 ft = (665,280)/(5280) = 126 miles

The dolphin can swim 126 miles in 3 hours

r = d/t

r = (126 miles)/(3 hours)

r = 42 miles per hour

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Part D

From my viewpoint, miles makes more sense because we have a smaller number which is easier to remember.

126 is smaller than 665,280

Also, 42 is much smaller than 221,760.