If 1/x = 1/5, what is x?

If 1/x = 1/5, what is x?

• A. -5
• B. -1
• C. 5
• D. 1

Answer: (C)

When two fractions are equal, their cross products match. Here 1/x = 1/5 means 1·5 = 1·x, so 5 = x. Therefore, x is 5. This makes the reciprocal of x equal to 1/5. The other options would give different reciprocals: -5 gives -1/5, -1 gives -1, and 1 gives 1.

When two fractions are equal, their cross products match. Here 1/x = 1/5 means 1·5 = 1·x, so 5 = x. Therefore, x is 5. This makes the reciprocal of x equal to 1/5. The other options would give different reciprocals: -5 gives -1/5, -1 gives -1, and 1 gives 1.