A can do a piece of work in 100 days, B and C together can do the same work in 20 days. If B can do the work in same time as that of C and A together then how long C alone can do the same work?

• 1/b=1/a+1/c means 1/b-1/c=1/100
  1/b+1/c=1/20
  equating this will get i/c=1/50
  so c will complete the work in 50 days if he work alone
  
• 8 years agoHelpfull: Yes(4) No(0)
• a=1/100,b+c=1/20
  a+b+c=6/100 ---> 1
  and b=c+a ----->2
  substitute 2 in 1 equation
  2(c+a)=6/100
  c=11/100 ,c can do in 100/11 days
  
  
• 8 years agoHelpfull: Yes(2) No(4)
• a=1/100 b+c=1/20
  a+b+c=6/100
  as per ques B can do the work in same time as that of C and A together hence b=a+c just subsitute b value in a+b+c equ...
  2(a+c)=6/100
  2a+2c=6/100
  2*(1/100)+2c=6/100
  1/50+2c=3/50
  2c=1/25
  c=1/50 hence c can complete the work in 50 days
  
  
• 8 years agoHelpfull: Yes(1) No(0)
• SAMATHA
  
  How u can combine equation 1 &2..?? Becoz these equations r not same type.
  Please see carefully @SAMATHA
• 8 years agoHelpfull: Yes(0) No(0)
• a=100 days so work is 1/100
  b+c=20 days work is 1/20
  then a+c+b=6/100-----1
  they said b=a+c-------2
  put 2 in 1,b+b=6/100,b=6/200
  put b and a in 2,c=1/50
  so c can do it in 50 days
  
• 8 years agoHelpfull: Yes(0) No(0)
• a=1/100,b+c=1/20
  b=a+c
  now a+b+c= 1/100+1/20=6/100------->1
  now pt b=a+c in eq 1
  a+a+c+c=6/100
  2(a+c)=6/100
  a+c=6/100*1/2=3/100
  we know a =1/100
  1/100+c=3/100
  c=3/100-1/100=2/100=1/50=50days
  put
• 5 years agoHelpfull: Yes(0) No(0)