Question

Set A contains 11 letters and 9 numbers. Set B contains 8 letters and 11 numbers. Five letters and 3 numbers are common to both sets A and B. Find the number of elements in set A or set B.

Answer 1

Answer:

There are 31 elements in set A or set B.

Step-by-step explanation:

Consider the provided information.

Set A contains 11 letters and 9 numbers.

Total there are 11+9=20 elements in set A.

Set B contains 8 letters and 11 numbers.

Total there are 8+11=19 elements in set B.

Five letters and 3 numbers are common to both sets A and B.

Total there are 5+3=8 elements common in both sets

Use the formula:

$A\cup B=A+B-(A\cap B)$

$A\cup B=20+19-8$

$A\cup B=31$

Hence, there are 31 elements in set A or set B.