Let m = {a, B, C, D} and p be the proper subset of M, then how many sets P are qualified at most?

Let m = {a, B, C, D} and p be the proper subset of M, then how many sets P are qualified at most?

They are {(empty set) {a, B, C} {a, B, D} {a, C, D} {B, C, D} {a, B} {a, C} {a, D} {B, C} {B, D} {C, D} {a} {B} {C} {D} so there are 15

Set M satisfying {a} ⊆ m ⊊ a, B, C, D} has ()
A. 6 B. 7 C. 8 d. 15

According to the meaning of the topic, the set M satisfying the meaning of the topic is {a}, {a, B}, {a, C}, {a, D}, {a, B, C}, {a, B, D}, {a, C, D}, a total of 7; so B

How many sets m satisfying the {a} subset m and the proper subsets {a, B, C, D,} are there?

True subsets do not include itself and empty sets. And the questions you give must have a, so there are six {{a, C, D} {a, B, D} {a, B, C} {a, D} {a, B} {a, C} {a}