On a test, the marks for ten students are: 2 students, 85%; 4 students, 78%; 3 students, 66%; and 1 student, 92%. What is the average mark on the test? (Exact
Answer)

77.2%

Step-by-step explanation:

The average formula is:

Let's first find the sum of all the numbers (remember sum means to add):

(2)(85) + (4)(78) + (3)(66) + 92 = ?

170 + 312 + 198 + 92 = 772

There are marks for 10 students so that is what goes at the bottom (10 students, 10 test scores)

Plug both things into the equation:

Therefore, the average mark on the test was 77.2%

Hope this helps!!

- Kay :)

i dont know sorry

step-by-step explanation:

center (1,3) with radius 6

step-by-step explanation:

we must complete the square to find the center and radius of the circle.

first make sure the x and y squared terms have 1 as their coefficients. we also make sure x and y terms together.

we now create space between the x and y terms with parenthesis.

we complete the square by taking the middle terms -2x and the -6y - divide each and square them.

we add the squares to both sides.

simplify.

and write the quadratics in factored form.

the center is (h,k) or (1,3). the radius is the square root of 36 which is 6.