document.write( "Question 1179861: A man is able to save #50 of his salary in a particular year ,after this,every year he saved #20 more than the preceeding year .how long does it take him to save #4370 \n" ); document.write( "
Algebra.Com's Answer #809434 by mananth(16946)![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "A man is able to save #50 of his salary in a particular year ,after this,every year he saved #20 more than the preceeding year .how long does it take him to save #4370\r \n" ); document.write( "\n" ); document.write( "First year 50 \n" ); document.write( "seond year 70 \n" ); document.write( "third year 90\r \n" ); document.write( "\n" ); document.write( "time = n = ?\r \n" ); document.write( "\n" ); document.write( "Sn = 4370\r \n" ); document.write( "\n" ); document.write( "Sn= [ (n/2)(2a+(n-1)d)]\r \n" ); document.write( "\n" ); document.write( "4370 = n/2[ 2*50 + (n-1)*20]\r \n" ); document.write( "\n" ); document.write( "8740= n(100+20n-20)\r \n" ); document.write( "\n" ); document.write( "8740 = n(80+20n)\r \n" ); document.write( "\n" ); document.write( "8740 = 80n +20n^2\r \n" ); document.write( "\n" ); document.write( "20n^2+80n-8740=0\r \n" ); document.write( "\n" ); document.write( "/20 \n" ); document.write( "n^2+4n -437=0\r \n" ); document.write( "\n" ); document.write( "(n-19)(n+23) =0\r \n" ); document.write( "\n" ); document.write( "Taking positive root \n" ); document.write( "n=19\r \n" ); document.write( "\n" ); document.write( "19 years\r \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |