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?	Options
A) 12 hours	B) 10 hours	C) 8 hours	D) 9 hours	E) None of these
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 &amp; c will produce (1/60)+(1/30)+(1/20)=1/10 million   Time taken to produce 1 million units=1/(1/10)= 
<gadget id="calculator">1/(1/10)</gadget>
<output>10</output>
10 hours   ANSWER:10 hours
<result>B</result>
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?