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Word problemsArithmeticMiddle schoolabout 1:17

A train travels 300 km in 2.5 hours. What is its speed?: animated lesson

A narrated, step-by-step word problems video lesson with captions. Final answer: Rate (speed) = 120 km per hour.

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. 1. The problem
    Worked example
    A train travels 300 km in 2.5 hours. What is its speed?
  2. 2. Steps, part 1
    1. Read the problem
    2. Identify the known values
    3. d=r td = r\,t
      Write the equation
    4. Solve for r
  3. 3. Steps, part 2
    1. Continue
    2. Result
  4. 4. The answer
    Rate (speed) = 120 km per hour\text{Rate (speed) = 120 km per hour}

    r = 120

  5. 5. Check
    • Substituting r = 120 back into d = r · t balances both sides ✓

Transcript

The problem. Here is the problem: A train travels 300 km in 2.5 hours. What is its speed? Distance 300 km, time 2.5 hours; the rate is unknown. Distance equals rate times time; d equals 300, t equals 2.5; solve for r.

Steps, part 1. Read the problem. Distance 300 km, time 2.5 hours; the rate is unknown. Identify the known values. Distance equals rate times time. Known: d equals 300, t equals 2.5. 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 300 over 2.5. Result. r equals 120.

The answer. So the answer is Rate (speed) equals 120 km 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 120 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.

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A train travels 300 km in 2.5 hours. What is its speed?