Let D = { j, k, l, m, n, o, p }

Question

Let D = { j, k, l, m, n, o, p }

Find the number of proper subsets for D.

Answer 1

the number of subsets is 2^n where n=# of elements of the set

set D has 7 elements

there are 2^7=128 subsets

therefore there are 128-1 proper subsets, or 127 proper subsets because we leave out the set D itself that contains all of the elements