The mean of a set of four test scores is 85. If three of the test scores are 81,83, and 85, what is the fourth test score?
A. 89
B. 87
C. 91
D. 85
Is the answer A?
Thank you
91
No it isn't A.
First, we get the total or sum of the four test scores by multiplying the mean by 4:
85 * 4 = 340
Then, we subtract this by the sum of the other three given test scores to find the fourth:
340 - (81 + 83 + 85) = ?
hope this helps~ `u`
Oh ok thank you.
Well, well, well! It seems like someone wants to play the guessing game with me! I must say, I'm quite the expert at that. Now, let's solve this riddle!
To find out the fourth test score, we need to find the sum of all four test scores first. So if the mean of the four scores is 85, and we know three of them are 81, 83, and 85, we can use a little bit of brain math to figure this out.
The sum of the four test scores would be 85 multiplied by 4 (because there are four test scores in total), which equals 340.
Now let's do the reverse math! If we subtract the sum of the first three scores (81 + 83 + 85) from 340, we'll be left with the fourth score. Let's see...
340 - (81 + 83 + 85) = 91
So, my dear friend, the fourth and final test score is 91, making the answer to your question C, not A. Better luck next time!
To find the missing test score, we can use the formula for calculating the mean of a set of values.
Mean = (sum of all values) / (number of values)
We are given that the mean is 85 and there are four test scores. Three of the test scores are 81, 83, and 85.
First, we need to find the sum of all four test scores:
Sum of all test scores = 81 + 83 + 85 + Fourth Test Score
We know that the mean is 85, so we can write the equation:
85 = (81 + 83 + 85 + Fourth Test Score) / 4
Now, we can solve for the fourth test score:
Multiply both sides of the equation by 4 to remove the division:
340 = 81 + 83 + 85 + Fourth Test Score
Combine like terms:
340 = 249 + Fourth Test Score
Subtract 249 from both sides of the equation:
340 - 249 = Fourth Test Score
Fourth Test Score = 91
So, the fourth test score is 91.
The answer is C) 91.