A student’s score on the first four mathematics tests of the year were 80, 95, 92 and 89. What must the student score on the fifth test so that the mean score for all five tests is exactly 90?

Needs a total of 450

450 - 80 - 95 - 92 - 89 = score need on last test

thanks

You're welcome.

To find out what score the student must get on the fifth test in order to achieve a mean score of 90 for all five tests, we can use the formula for calculating the mean:

Mean = (Sum of all scores) / (Number of scores)

Let's follow these steps to find the answer:

Step 1: Calculate the sum of the scores on the first four tests.
Sum = 80 + 95 + 92 + 89 = 356

Step 2: Determine the number of scores (in this case, it's 4 because the student has taken four tests).

Step 3: Let "x" be the score the student needs on the fifth test.

Step 4: Write an equation to solve for "x":
(Sum + x) / (Number of scores + 1) = Mean

Plugging in the given values:
(356 + x) / (4 + 1) = 90

Step 5: Solve the equation for "x":
Multiply both sides of the equation by (4 + 1) to eliminate the fraction:
356 + x = 450

Subtract 356 from both sides:
x = 450 - 356
x = 94

Therefore, the student must score at least 94 on the fifth test to achieve a mean score of exactly 90 for all five tests.