document.write( "Question 477178: James has two malfunctioning robots. One of theme beeps every 4 seconds; the other beeps every 9 seconds. If they are turned on at exactly the same time, how many times during the next hour will both robots beep at the same time?\r
\n" ); document.write( "\n" ); document.write( "Please clearly explain how I could approach and solve this, thanks! \n" ); document.write( "

Algebra.Com's Answer #327157 by Edwin McCravy(20056) $\"\"$ $\"About$

You can put this solution on YOUR website!
James has two malfunctioning robots. One of theme beeps every 4 seconds; the other beeps every 9 seconds. If they are turned on at exactly the same time, how many times during the next hour will both robots beep at the same time?\r
\n" ); document.write( "\n" ); document.write( "

\r\n" );
document.write( "The first one beeps when multiples of 4 seconds have passed, when these\r\n" );
document.write( "numbers of seconds have passed:\r\n" );
document.write( "\r\n" );
document.write( "4,8,16,20,24,28,32,36,40,44,48,52,56,60,64,68,72,76,...\r\n" );
document.write( "\r\n" );
document.write( "The second one beeps when multiples of 9 seconds have passed, when these\r\n" );
document.write( "numbers of seconds have passed:\r\n" );
document.write( "\r\n" );
document.write( "9,18,27,36,45,54,63,72,81...\r\n" );
document.write( "\r\n" );
document.write( "They will beep together when the numbers of seconds have passed which\r\n" );
document.write( "are common multiples of both 4 and 9. which are the multiples of their\r\n" );
document.write( "LCM, which is 36.\r\n" );
document.write( "\r\n" );
document.write( "Now we need to find how many multiples of 36 seconds there are in\r\n" );
document.write( "an hour.\r\n" );
document.write( "\r\n" );
document.write( "An hour is 60 minutes long and each minute is 60 seconds long, so \r\n" );
document.write( "\r\n" );
document.write( "1 hour is 3600 seconds long.  We divide 3600 by 36 and get 100.  \r\n" );
document.write( "\r\n" );
document.write( "So they will beep together 100 times in the next hour.\r\n" );
document.write( "\r\n" );
document.write( "Edwin

\n" ); document.write( " \n" ); document.write( "

\n" );