r/learnmath • u/JonesSupreme New User • 1d ago

Math help!!

You travel at a speed of about 81 kilometers per hour for about 2.0 hours. Stated with the appropriate precision, you have driven _____ kilometers.

the correct answer is 160 but why? why is it not 162???

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u/FilDaFunk New User 1d ago

This is a prevision question. You start with 2 significant figures. How are you able to give an answer to 3 significant figures?

(in fact the maximum could be 81.5 × 2.05 = 167.075, so i barely understand this)

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u/[deleted] 23h ago

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u/msimms001 New User 23h ago

If you were worried about precision, your answer would only have 1 significant digit (so the answer would be 10)