BTGmoderatorLU wrote:How many papers can Bill and Tim proofread in 60 minutes if they are working together?

(1) Bill can proofread twice as many papers as Tim in the same time period.
(2) Tim can proofread 30 fewer papers than Bill in 60 minutes.

The OA is C.

Please, can anyone assist with this DS question? I need help. Can I write 2 equations to solve it? I'm not sure. Thanks!

We have to find out the number of papers Bill and Tim can proofread in 60 minutes if they are working together.

Let's take each statement one by one.

(1) Bill can proofread twice as many papers as Tim in the same time period.

We do not have the rate of Tim; thus, we cannot find the rate of Bill and their combined rate. Insufficient.

(2) Tim can proofread 30 fewer papers than Bill in 60 minutes.

We do not know how many papers Bill can proofread in 60 minutes; thus, we cannot find the number of papers Tim can proofread and their combined rate. Insufficient.

(1) and (2) together

From Statement 1: Say the rate of Tim is x; thus the rate of Bill = 2x. They together can proofread x + 2x = 3x papers.
From Statement 2: 2x - x = 30 => x = 30.

They together proofread 3x = 90 papers in 60 minutes.

The correct answer: C

Hope this helps!

-Jay
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