document.write( "Question 1186342: At exactly 12 o’clock noon the hour hand of a clock begins to move at twice its
\n" );
document.write( "normal speed, and the minute hand begins to move backward at half its normal
\n" );
document.write( "speed. When the two hands next coincide, what will be the correct time? \n" );
document.write( "
Algebra.Com's Answer #817254 by greenestamps(13200)![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "The normal angular speed for the hour hand is 30 degrees per hour, clockwise of course. So starting at 12:00 noon this clock's hour hand starts moving at 60 degrees per hour, still clockwise. \n" ); document.write( "The normal angular speed for the minute hand is 360 degrees per hour, clockwise. So starting at 12:00 noon this clock's minute hand starts moving at 180 degrees per hour, counterclockwise. \n" ); document.write( "For the hands to meet after 12:00, the two hands need to move a total of 360 degrees. \n" ); document.write( "Let t be the number of hours after 12:00 where the hands meet again. \n" ); document.write( "60t+180t=360 \n" ); document.write( "240t=360 \n" ); document.write( "t=360/240=3/2 or 1.5 \n" ); document.write( "ANSWER: It will take 1.5 hours starting at 12:00 for the two hands to meet again; so the correct time will be 1:30pm. \n" ); document.write( " \n" ); document.write( " |