document.write( "Question 937145: Randy and Paul can do a piece of work in 10 days ;Randy and Guy can do it in 8 days ;Paul and Guy can do it in 12 days. How long will it take to each to do it alone ? \n" ); document.write( "
Algebra.Com's Answer #570572 by ptaylor(2198) You can put this solution on YOUR website! Let R= amount of time it takes Randy to do the work alone \n" ); document.write( "Then Randy works at the rate of 1/R of the job per day \n" ); document.write( "Let P= amount of time it takes Paul to do the work alone \n" ); document.write( "Then Paul works at the rate of 1/P of the job per day \n" ); document.write( "Let G=amount of time it takes Guy to do the work alone \n" ); document.write( "Then Guy works at the rate of 1/G of the job per day \n" ); document.write( "Sooooo our equations to solve are: \n" ); document.write( "1/R+1/P=1/10---------------------eq1 \n" ); document.write( "1/R+1/G=1/8------------------------eq2 \n" ); document.write( "1/P+1/G=1/12--------------------------eq3\r \n" ); document.write( "\n" ); document.write( "Subtract eq2 from eq1 and we get: \n" ); document.write( "1/P-1/G=(1/10)-(1/8)=(4/40)-(5/40)=-1/40 add this to eq3 \n" ); document.write( "2/P=(1/12)-(1/40)=(10/120)-(3/120)=7/120 \n" ); document.write( "2/P=7/120 \n" ); document.write( "1/P=7/240 substitute this into eq1-----------------EQ1a \n" ); document.write( "1/R=(1/10)-(7/240)=(24/240)-(7/240)=17/240 \n" ); document.write( "1/R=17/240 substitute this into eq2-----------------EQ2a \n" ); document.write( "17/240 + 1/G=1/8 \n" ); document.write( "1/G=(1/8)-(17/240)=(30/240)-(17/240)=13/240 \n" ); document.write( "1/G=13/240------------------------------------------EQ3a \n" ); document.write( "From eq2a: (you can divide these out but it's easier to work in fractions when checking your work) \n" ); document.write( "17R=240 \n" ); document.write( "R=240/17 days \n" ); document.write( "From eq1a: \n" ); document.write( "7P=240 \n" ); document.write( "P=240/7 days \n" ); document.write( "From eq3a: \n" ); document.write( "13G=240 \n" ); document.write( "G=240/13 days \n" ); document.write( "CK \n" ); document.write( "Randy and Paul \n" ); document.write( "(17/240)+(7/240)=????1/10 \n" ); document.write( "24/240=1/10 \n" ); document.write( "1/10=1/10 \n" ); document.write( "Randy and Guy \n" ); document.write( "(17/240)+(13/240)=????1/8 \n" ); document.write( "30/240=1/8 \n" ); document.write( "1/8=1/8 \n" ); document.write( "Paul and Guy \n" ); document.write( "(7/240)+(13/240)=????1/12 \n" ); document.write( "20/240=1/12 \n" ); document.write( "1/12=1/12\r \n" ); document.write( "\n" ); document.write( "Does this help?---ptaylor\r \n" ); document.write( " \n" ); document.write( " \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |