A set of n elements has 2n subsets. Our set has 4 subsets. Thus, we have the equation
2n =

That should be 2^n and not just 2n

If we have 4 subsets, then 2^n = 4 leads to n = 2 since 2^2 = 4.

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Here's an example.

A = {p,q}

The four subsets of set A = {p,q} are

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Here's an example with n = 3 elements. We'll have 2^n = 2^3 = 8 subsets now. Let's say we had B = {r,s,t}

Those 8 subsets of set B are...

Note that order does not matter within any given set. Something like {r,s} is the same as {s,r}.

answer: the answer is one of

step-by-step explanation:   we are given to write a proper fraction where the whole is divided into an even number of equal parts less than ten, and an odd number of those parts exist.

an even number less than 10 may be one of 2, 4, 6 or 8. so, the whole may be one of these four evens.

now, an odd number of these parts must exist, so the numerator must be an odd number, one of 1, 3, 5 or 7. it cannot be 9 because then the fraction will become improper.

thus, our fraction may be one of the following