Q. 3 machines a,b,c can be used to produce a product. Machine a will take 60 hours to produce a million units. Machine b is twice as fast as machine a. Machine c takes the same amount of time as machine a and b taken together. How much time will be required to produce a million units if all the three machines are used simultaneously?
Option
(a) 12 hours
(b) 10 hours
(c) 8 hours
(d) None of these

• (b) 10 hours
  1 hour capacity of
  Machine a =1/60 million
  Machine b =2*(1/60)=1/30 million
  Machine c =(1/60)+(1/30)=1/20 million
  So in 1 hour Machines a,b & c will produce (1/60)+(1/30)+(1/20)=1/10 million
  Time taken to produce 1 million units=1/(1/10)=10 hours
• 11 years agoHelpfull: Yes(0) No(0)
• machine a produce in 1 hr = 1/60 million
  machine b produce in 1 hr = 1/30
  machine c produce in 1 hr = (1/60)+(1/30)=1/20
  1 hr work of all machines a b c = (1/60)+(1/30)+(1/20)
  =1/10
  time required to produce a million units= 10 hrs ans...
• 11 years agoHelpfull: Yes(0) No(0)
• (b)10 hours
  
• 9 years agoHelpfull: Yes(0) No(0)
• b) 10 hrs
  a = 1/60
  b = 2*1/60 = 1/30
  c = 1/60 + 1/30 = 1/20
  a + b + c = 1/60 + 1/30 + 1/20 = 1/10
• 8 years agoHelpfull: Yes(0) No(0)