A company has two types of machines, type R and type S. Operating at a constant rate, a machine of type R does a certain job in 16 hrs and a machine of type S does the same job in 8 hours. If the company used the same number of each type of machine to do the job in 2 hours, how many machines of type R were used?	Choose the correct choice from the following
A) A)3  B) B)4  C) C)6  D) D)9  E) E)12
Rate of machine R =1/16   Rate of machine S =1/8   since same no of machines used for R and S to do the same work in 2 hrs   So collective rate needed to finish the work in 2 hrs= 1/2   Let the no of machine be x   So, x/16 +x/8 =1/2   3x/16=1/2   x=16/6=3   So no of machine R is 3   3nswer 3
<result>A</result>
A company has two types of machines, type R and type S. Operating at a constant rate, a machine of type R does a certain job in 16 hrs and a machine of type S does the same job in 8 hours. If the company used the same number of each type of machine to do the job in 2 hours, how many machines of type R were used?