document.write( "Question 1165986: its nine o'clock . how long will it be before both hands are pointing in the same direction? \n" ); document.write( "
Algebra.Com's Answer #790463 by Theo(13342)\"\" \"About 
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a full cycle of the clock is 360 degrees.\r
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\n" ); document.write( "\n" ); document.write( "the hour hand does this in 12 hours.
\n" ); document.write( "therefore, the speed of the hour hand is 360 / 12 = 30 degrees per hour.\r
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\n" ); document.write( "\n" ); document.write( "the minute hand does this in 1 hour.
\n" ); document.write( "therefore, the speed of the minute hand is 360 degrees per hour.\r
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\n" ); document.write( "\n" ); document.write( "rate * time = distance.\r
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\n" ); document.write( "\n" ); document.write( "the rate is in degrees per hour.
\n" ); document.write( "the time is in hours.
\n" ); document.write( "the distance is in degrees.\r
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\n" ); document.write( "\n" ); document.write( "when they start, the hour hand is at 9 * 30 = 270 degrees and the minute hand is at 0 degrees.\r
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\n" ); document.write( "\n" ); document.write( "for the hour hand, rate * time = distance becomes 30 * T + 270 = D.
\n" ); document.write( "for the minute hand, rate * time = distance becomes 360 * T = D.\r
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\n" ); document.write( "\n" ); document.write( "note that 30 * T + 270 = D is equivalent to 30 * T = D - 270.
\n" ); document.write( "this means the hour hand needs to move 270 degrees less than the minute hand for them to be equal to the same number of degrees on the clock.\r
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\n" ); document.write( "\n" ); document.write( "the two equations that need to be solved simultaneously are:\r
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\n" ); document.write( "\n" ); document.write( "30 * T + 270 = D
\n" ); document.write( "360 * T = D\r
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\n" ); document.write( "\n" ); document.write( "since they are both equal to D, then 30 * T + 270 = 360 * T
\n" ); document.write( "subtract 30 * T from both sides of this equation to get:
\n" ); document.write( "270 = 330 * T
\n" ); document.write( "solve for T to get:
\n" ); document.write( "T = 270 / 330 = .8181818181..... hours.\r
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\n" ); document.write( "\n" ); document.write( "in .8181818181..... hours, .....\r
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\n" ); document.write( "\n" ); document.write( "the hour hand will have moved from 270 degrees to 294.54545454..... degrees.
\n" ); document.write( "the minute hand will have moved from 0 degrees to 294.54545454..... degrees.\r
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\n" ); document.write( "\n" ); document.write( "they will both be pointing in the same direction on the clock.\r
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\n" ); document.write( "\n" ); document.write( "the time will be 9 + .8181818181... = 9.8181818181 hours.
\n" ); document.write( "that's equivalent to 9 hours and 49.0909090909... minutes.\r
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\n" ); document.write( "\n" ); document.write( "round to the nearest minute and that becomes 9:49 on the clock.\r
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\n" ); document.write( "\n" ); document.write( "round to the nearest second and that becomes 9:49:05 on the clock.\r
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\n" ); document.write( "\n" ); document.write( "here's a visual display of what it looks like at 9:49:05 on the clock.\r
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\n" ); document.write( "\n" ); document.write( "the hour hand is in orange.
\n" ); document.write( "the minute hand is in green.
\n" ); document.write( "you can't see the hour hand because the minute hand is covering it.
\n" ); document.write( "the pointer handle for the minute hand is further away from the center of the clock than the pointer handle for the hour hand.
\n" ); document.write( "the pointer handles are the blue circles that you see on the hands of the clock.\r
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