What is the mean value in the list: 1,3,5,5,5,7,8,8

The mean is also known as the average. Take the sum of all the numbers, and divide it by the amount of numbers you added together. Like this:

1+3+5+5+5+7+8+8=42

Now divide by 8 because there are 8 numbers.

42/8= 5.25.

Your average or mean is 5.25 or 5 1/4

Add all of the values ;1,3,5,5,5,7,8,8=42
divide 42 by the amount of numbers which is 8
42/8=5.25

In the first triangle 80+20+p=180 (since sum of all angles of a triangle is 180)so p= 80also in second triangle 55+45+q=180 (since sum of all angles of a triangle is 180)so q=80so we can conclude that p=80 degrees q=80 degrees so p=q=80 degreeshence option b is correct