Brittany's first four quiz grades are 78 81 69 and 94 what would her next quiz score need to be in order to have a mean score of 79

The mean is the sum of all numbers divided by the number of numbers. We can set up an equation:



Where 'x' is the next quiz score she need. Solve for 'x'. Multiply 5 to both sides:



Add:



Subtract 322 to both sides:



So her next quiz score needs to be 73 in order to have a mean score of 79  on all her quizzes.