Each of 10 machines works at the same constant rate doing a certain job. the amount of time needed by the 10 machines, working together, to complete the job is 16 hours.
how many hours would be needed if only 8 machines, working together, were used to complete the job?

a. 18
b. 20
c. 22
d. 24
e. 26

Step-by-step explanation:

Let w be the work and r be the rate at which one machine is doing the work.

The amount of time needed by the 10 machines, working together, to complete the job is 16 hours.

            Work done by machine = Number of machines x Rate at which one machine is doing the work x Time

            w = 10 x r x 16

Now we need to find time taken t by 8 machines to the same work.

            Work done by machine = Number of machines x Rate at which one machine is doing the work x Time

             w = 8 x r x t

Time taken 8 machines to the same work = 20 hours    

Option B is the correct answer.        

i dony know

step-by-step explanation:

step-by-step explanation:

we are given

since, we have to isolate x on anyone side

so, we can move all x terms on one side

subtract both sides by 2x

add both sides by 9

divide both sides by 4

we get