Answer:
C. 81
Step-by-step explanation:
The new mean is 66.09
<u>Explanation:</u>
Mean weight of 20 students = 65kg
One student with 88kg entered the room.
New mean = ?


The above equation can further be written as:

New mean = 
= 66.09
Therefore, the new mean is 66.09
To solve this you must use the rules of PEMDAS (Parentheses, Exponent, Multiplication, Division, Addition, Subtraction)
First we have parentheses.
-4(3 - 1) + 2
3 - 1 = 2
-4(2) + 2
We have no exponents so go on to multiplication
-4(2) + 2
-4 * 2 = -8
-8 + 2
No division so go to addition
-8 + 2
When adding a positive number with a negative number you will act as if you are subtracting the two numbers, then take the sign of the largest number (disregarding the signs). In this case the largest number is 8 and its sign is negative. Your answer will have a negative sign.
-6
Hope this helped!
~Just a girl in love with Shawn Mendes