Write down all elements of ({9, 10, 11} ∩ {10, 11, 12, 13}) ∪ {14, 15}. (enter your answer in set notation.)

What we have so far:

Let set A = { 9, 10, 11}

Let set B = {10, 11, 12, 13}

Let set C = A ∩B. This means: the intersection of A & B.

Let set D = { 14, 15}

Let set Universal = C ∪D. This means: the union of C & D where C is the intersection of A & B.

Solution:

Let us first solve for set C.

C = A∩B

C = {9, 10, 11} ∩ {10, 11, 12, 13}

C = {10, 11} < - - - New value for set C

Let us now solve for set Universal.

Universal = C∪D

Unviversal = {10, 11} ∪ {14, 15}

∴ Universal = {10, 11, 14, 15} < - - - What we are looking for.

Therefore, the answer is Universal = {10, 11, 14, 15}.