Six machines, each working at the same constant rate, together can complete a job in 12 days. How many additional machines, each working at the same constant rate, will be needed to complete the job in 8 days?

(A) 2

(B) 3

(C) 4

(D) 6

(E) 8

Question

Mathematics

Xander Wolf

28 June, 04:06

Six machines, each working at the same constant rate, together can complete a job in 12 days. How many additional machines, each working at the same constant rate, will be needed to complete the job in 8 days?

(A) 2

(B) 3

(C) 4

(D) 6

(E) 8

+3

Answers (1)

Know the Answer?

Gianna Heath · Answer 1

B. 3 more.

Step-by-step explanation:

If the time for each of the machines working alone to complete the job = x hours then

6 * 1/x = 1/12

1/x = 1/12/6 = 1/72

x = 72 days.

So we have the equation

y * 1/72 = 1/8

y = 72/8 = 9.

Six machines, each working at the same constant rate, together can complete a job in 12 days. How many additional machines, each working at the same constant rate, will be needed to complete the job in 8 days?(A) 2(B) 3(C) 4(D) 6(E) 8

Six machines, each working at the same constant rate, together can complete a job in 12 days. How many additional machines, each working at the same constant rate, will be needed to complete the job in 8 days?

(A) 2

(B) 3

(C) 4

(D) 6

(E) 8