Bunuel wrote:

How long does it take Lee to type a certain document?

Time = Job/Rate

(1) Lee types at a rate of 45 words per minute. We have the rate only. Not sufficient.

(2) Typing at a rate of 50 words per minute, Kim can type the document in 1.4 minutes --> Job = Rate*Time = 50*1.4 = 70 pages. We have only the amount f the job to be done. Not sufficient.

(1)+(2) We know both the rate and the amount of the job, hence we can get the time needed to complete it. Sufficient.

Answer: C.

Bunuel wrote:

How long does it take Lee to type a certain document?

Time = Job/Rate

(1) Lee types at a rate of 45 words per minute. We have the rate only. Not sufficient.

(2) Typing at a rate of 50 words per minute, Kim can type the document in 1.4 minutes --> Job = Rate*Time = 50*1.4 = 70 pages. We have only the amount f the job to be done. Not sufficient.

(1)+(2) We know both the rate and the amount of the job, hence we can get the time needed to complete it. Sufficient.

Answer: C.

But Bunuel nowhere it says that they were typing the same document ....what if the document given to kim and lee are different ?