tom scores 83,88,75, and 90 on the first 4 tests in algebra. what does he need to get on the 5th test to have an average of 85?
You can also do this problem this way:
(83+88+75+90+x)/5=85
Assuming that the total possible score on each test, then the total possible points for 5 tests is 100.
0.85 * 500 = 425
He has a total of 336 points now.
425 - 336 = 89
To find out what Tom needs to score on the 5th test to have an average of 85, we need to use the formula for the average. The average is calculated by adding up all the scores and dividing by the number of tests.
Let's break it down step by step:
1. Find the sum of the first four test scores: 83 + 88 + 75 + 90 = 336.
2. Add the score Tom needs on the 5th test to the sum: 336 + X (the score on the 5th test).
3. Divide the total sum by 5 (the total number of tests) to find the average: (336 + X) / 5.
Now we can set up an equation to solve for X:
(336 + X) / 5 = 85
To solve for X, we'll first multiply both sides by 5 to get rid of the denominator:
336 + X = 85 * 5
Simplifying the right side of the equation:
336 + X = 425
Next, subtract 336 from both sides of the equation to isolate X:
X = 425 - 336
Simplifying:
X = 89
Therefore, Tom needs to score 89 on the 5th test in order to have an average of 85.