Bunuel wrote:

Of the companies surveyed about the skills they required in prospective employees, 20 percent required both computer skills and writing skills. What percent of the companies surveyed required neither computer skills nor writing skills?

(1) Of those companies surveyed that required computer skills, half required writing skills.

(2) 45 percent of the companies surveyed required writing skills but not computer skills.

We can use the formula:

Total = Computer + Writing - Both + Neither

So in terms of percentage, we have:

100 = Computer + Writing - 20 + Neither

120 = Computer + Writing + Neither

We need to determine Neither, so we need to know Computer and Writing.

Statement One Only:

Of those companies surveyed that required computer skills, half required writing skills.

This means computer skills must be 40 since half of it is 20, which is both computer and writing skills. Therefore, we have:

120 = 40 + Writing + Neither

However, without knowing the value of Writing, we can’t determine Neither. Statement one alone is not sufficient.

Statement Two Only:

45% of the companies surveyed required writing skills but not computer skills.

Notice writing skills only = Writing - Both, so 45 = Writing - 20 or Writing = 65. So we have:

120 = Computer + 65 + Neither

However, without knowing the value of Computer, we can’t determine Neither. Statement two alone is not sufficient.

Statements One and Two Together:

With both statements, we have:

120 = 40 + 65 + Neither

15 = Neither

Answer: C

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