A company has two models of computers, model M and

[M7MBA]

A company has two models of computers, model M and model N. Operating at a constant rate, a model M computer can complete a certain task in 18 minutes and a model N computer can complete the same task in 9 minutes. If the company used the same number of each model of computer to complete the task in 1 minute, how many model M computers were used?

(A) 2

(B) 3

(C) 6

(D) 9

(E) 12

The OA is the option C.

What is the equation that I should set in order to solve this PS question? Can anyone help me? Please.

[Vincen]

A company has two models of computers, model M and model N. Operating at a constant rate, a model M computer can complete a certain task in 18 minutes and a model N computer can complete the same task in 9 minutes. If the company used the same number of each model of computer to complete the task in 1 minute, how many model M computers were used?

(A) 2

(B) 3

(C) 6

(D) 9

(E) 12

The OA is the option C.

What is the equation that I should set in order to solve this PS question? Can anyone help me? Please.

Hello M7MBA.

Let's see.

- The time taken by model M computer to complete 1 work is 18 minutes. So the rate of work of model M is 1/18 work/min.

- The time taken by model N computer to complete 1 work is 9 minutes. So the rate of work of model N = 1/9 work/min.

- 1 work was completed in 1 minute, then the combined rate of work of "x" computers of M type and "x" computers of N type = 1 work/min.

Now, this implies that $$x\cdot\frac{1}{18}+x\cdot\frac{1}{9}=1\ \Rightarrow\ \ 3x=18\ \Rightarrow\ \ x=6.$$ This implies that the company used 6 Model M Computers to make the task.

Therefore, the correct answer is the option C.

I hope it can helps you.

[GMATGuruNY]

A company has two models of computers, model M and model N. Operating at a constant rate, a model M computer can complete a certain task in 18 minutes and a model N computer can complete the same task in 9 minutes. If the company used the same number of each model of computer to complete the task in 1 minute, how many model M computers were used?

(A) 2

(B) 3

(C) 6

(D) 9

(E) 12

Let the task = 18 units.
Since M takes 18 minutes to complete the 18-unit task, M's rate = w/t = 18/18 = 1 unit per minute.
Since N takes 9 minutes to complete the 18-unit task, N's rate = w/t = 18/9 = 2 units per minute.
Combined rate for M+N = 1+2 = 3 units per minute.
For the 18-unit task to be completed in 1 minute, the required rate = w/t = 18/1 = 18 units per minute.
Since the rate for M+N = 3 units per minute, the number of M+N's required to produce 18 units per minute = (required rate)/(rate for M+N) = 18/3 = 6.

The correct answer is C.

[Scott@TargetTestPrep]

A company has two models of computers, model M and model N. Operating at a constant rate, a model M computer can complete a certain task in 18 minutes and a model N computer can complete the same task in 9 minutes. If the company used the same number of each model of computer to complete the task in 1 minute, how many model M computers were used?

(A) 2

(B) 3

(C) 6

(D) 9

(E) 12

We are given that the model M computer can complete a task in 18 minutes; thus, the rate of model M is 1/18. We are also given that a model N computer can complete the same task in 9 minutes; thus, the rate of model N is 1/9.

We need to determine the number of each model of computer used if the task were completed in 1 minute. If that is the case, then the combined rate of all the computers is 1/1 = 1. We can let n = the number of computers used for each model of computer and create the following equation:

rate of n model M computers + rate of n model N computers = 1

n(1/18) + n(1/9) = 1

Multiplying the entire equation by 18, we have:

n + 2n = 18

3n = 18

n = 6

Answer: C