WEBVTT

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Here is the problem: A train travels 300 km in 2.5 hours. What is its speed?

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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.

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Read the problem. Distance 300 km, time 2.5 hours; the rate is unknown.

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Identify the known values. Distance equals rate times time. Known: d equals 300, t equals 2.5. Unknown: rate (speed) (r).

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Write the equation. d equals r times t.

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Solve for r. Divide both sides by t: r equals d / t.

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Continue. r equals 300 over 2.5.

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Result. r equals 120.

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

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Substitute the known values into d equals r times t and isolate r. Keep units consistent (for example miles, miles per hour and hours).

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Substituting r equals 120 back into d equals r times t balances both sides, which checks out.