PLS HURRY ASAP WILL MARK THE BRAINILEST The mean (average) of 4 numbers is 88.
What is the fourth number if three of the numbers are 80, 95, and 85?

A. 92
B. 54
C. 75
D. 99
E. None of these

Step-by-step explanation:

Add up the four test scores (80, 95, 85, x) then divide by 4 and set that result equal to 88. The equation you get is (80+95+85+x)/4 = 88. Now solve for x.

(80+95+85+x)/4 = 88

(260+x)/4 = 88

4*(260+x)/4 = 4*88

260+x = 352

x+260 = 352

x+260-260 = 352-260

x = 92

The fourth missing number is 92

option (b) is correct

step-by-step explanation:

to find the solution of this system, we need to convert it into reduced row-echelon form. we have,

after applying row operations r2 -> r2/2 and r3 -> r3/3, we get,