Question

If C = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10} and D = {numbers divisible by 3 from 1 to 21}, what is C ∩ D?

{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 15, 18, 21}

{3, 6, 9, 12, 15, 18, 21}

{3, 6, 9}

{ }

Question 4 (Multiple Choice Worth 3 points)

[3.02]

If A = {onion, pickles} and B = {onions, pickles, mustard, mayonnaise, lettuce}, what is A union B?

{onions, pickles}

{onions, pickles, mustard, mayonnaise, lettuce}

{mustard, mayonnaise, lettuce}

{ }

Answer 1

\[C\cap D\] is what is common to both C and D

Answer 2

\[C = \{1, 2, 3, 4, 5, 6, 7, 8, 9, 10\} \]
\[D=\{3,6,9,12,15,18,21\}\]

Answer 3

pick out the numbers that are on both sets

Answer 4

Sn=An(1-r^n)/1-r