Division Problem: 90 people were invited to the party.
1. How many tables are needed, if each table can seat 8 people?
2. How many tables will be completely full?
3. How many people will be at an incomplete table?
Solution:
You have that 90=8·11+2 (8 - divisor, 11 - quotient, 2 - remainder).
Since the quotient is 11, 12 tables are needed, 11 tables will be completely full and the last 12th table will be incomplete, only 2 people will be at this table.
Answer: 1. 12 tables, 2. 11 tables, 3. 2 people
The formulas for conditional probability are:


.
Since

and

, you have the equation

.
Therefore,

.
Answer: The correct choice is D.
Not sure but I believe letter B) 3+4 is rational since the answer is 7 and 7 is a rational number and it can be expressed as a quotient. The sum of a rational number and an irrational number is irrational. The sum of two rational numbers is rational