document.write( "Question 1005922: Martin won the 400 meter race in the school sports with a time of 1 minute. The distance was correct to the nearest centimeter. The time was correct to the nearest tenth of a second.
\n" ); document.write( "Work out the upper bound and the lower bound of Martin’s speed in km/h. Give your answer correct to 5 significant figures. Thanks! \n" ); document.write( "

Algebra.Com's Answer #622397 by KMST(5328) $\"\"$ $\"About$

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The race distance was supposed to be 400.00m,
\n" ); document.write( "but maybe it was really up to 0.5cm longer than that, at 400.005m,
\n" ); document.write( "or maybe it was really up to 0.5cm shorter than that, at 399.995m.
\n" ); document.write( "So, $\"399.995m%3C=distance%3C=400.005m\"$ .
\n" ); document.write( "Maybe Martin finished in up to 0.05 second less than 1 minute, at 59.95 seconds,
\n" ); document.write( "or maybe Martin finished in up to 0.05 second less than 1 minute, at 60.05 seconds.
\n" ); document.write( "So, $\"60.05s%3E=time%3E=59.95s\"$ .
\n" ); document.write( "Then,
\n" ); document.write( " $\"system%28399.995m%3C=distance%3C=400.005m%2C60.05s%3E=time%3E=59.95s%29\"$ ---> $\"399.995m%2F%2260.05+s%22%3C=distance%2Ftime%3C=400.005m%2F%2259.95+s%22\"$ ---> $\"6.61032\"$ $\"m%2Fs%3C=speed%3C=6.67231\"$ $\"m%2Fs\"$ .
\n" ); document.write( "The numbers above were rounded to 6 significant figures, because they are intermediate results
\n" ); document.write( "Lower bound = $\"6.61032\"$ $\"m%2Fs\"$ $\"%281km%2F%221000+m%22%29%283600s%2F%221+h%22%29=%2224.020+km+%2Fh%22\"$ (with 5 significant figures reported).
\n" ); document.write( "Upper bound = $\"6.67231\"$ $\"m%2Fs\"$ $\"%281km%2F%221000+m%22%29%283600s%2F%221+h%22%29=%2223.980+km+%2Fh%22\"$ (with 5 significant figures reported). \n" ); document.write( "

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