A company has two types of machines, type R and type S.
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 40 hrs and a machine of type S does the same job in 20 hours. If the company used the same number of each type of machine to do the job in 4 hours, how many machines of type R were used?
Answer/Solution
10/3
Steps/Work
Rate of machine R =1/40
Rate of machine S =1/20
since same no of machines used for R and S to do the same work in 4 hrs
So collective rate needed to finish the work in 4 hrs= 1/4
Let the no of machine be x
So, x/40 +x/20 =1/4
3x/40=1/4
x=10/3
So no of machine R is 10/3
Answer B
Rate of machine S =1/20
since same no of machines used for R and S to do the same work in 4 hrs
So collective rate needed to finish the work in 4 hrs= 1/4
Let the no of machine be x
So, x/40 +x/20 =1/4
3x/40=1/4
x=10/3
So no of machine R is 10/3
Answer B