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Word problemsArithmeticMiddle schoolabout 1:15

A car travels 150 miles in 3 hours. What is its average speed?: animated lesson

A narrated, step-by-step word problems video lesson with captions. Final answer: Rate (speed) = 50 miles per hour.

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Video with a synthetic English voice and captions. Pick another language for subtitles in that language, or open the interactive version.

Video narrated by a synthetic voice (Piper TTS, en_US-ljspeech-high voice (LJ Speech dataset, public domain)); the steps come from our maths engine and the answer was checked independently. Download MP4 (0.5 MB) · Captions (WebVTT)

Steps on screen

1. The problem
Worked example
A car travels 150 miles in 3 hours. What is its average speed?
2. Steps, part 1
1. Read the problem
2. Identify the known values
3. $d = r\,t$
  Write the equation
4. Solve for r
3. Steps, part 2
1. Continue
2. Result
4. The answer
$\text{Rate (speed) = 50 miles per hour}$
r = 50
5. Check
- Substituting r = 50 back into d = r · t balances both sides ✓

Transcript

The problem. Here is the problem: A car travels 150 miles in 3 hours. What is its average speed? Distance 150 miles, time 3 hours; the rate is unknown. Distance equals rate times time; d equals 150, t equals 3; solve for r.

Steps, part 1. Read the problem. Distance 150 miles, time 3 hours; the rate is unknown. Identify the known values. Distance equals rate times time. Known: d equals 150, t equals 3. Unknown: rate (speed) (r). Write the equation. d equals r times t. Solve for r. Divide both sides by t: r equals d / t.

Steps, part 2. Continue. r equals 150 over 3. Result. r equals 50.

The answer. So the answer is Rate (speed) equals 50 miles per hour. Substitute the known values into d equals r times t and isolate r. Keep units consistent (for example miles, miles per hour and hours).

Check. Substituting r equals 50 back into d equals r times t balances both sides, which checks out.

About word problems

Turn everyday situations about prices, speed, ages and interest into equations and solve them.

A car travels 150 miles in 3 hours. What is its average…