If your test grade averages out to be 81 what grade would you need to make on your next test to keep a 70 avg.

Question

please show me how you got this answer if al possible,thanks!!

Answer 1

i'm just going to assume that there's onlie 1 test in that category because it kind of depends on how many tests there are... a rough estimate would be you have an 81/100 ... now in order to keep a 70 average, you would need a combined score from both of those tests to be AT LEAST 140/200 (which is basically a 70% / 70 average)

140-81 = 59...

so you'd basically need to get at least a 59 for your next test...

*** note this is only based on you having only taken ONE (1) test...
** this is also with the assumption that each test is weighted the same, and they are out of basically 100 points or the grades are based on a percentage scale

hope this helps..

Answer 2

Depends on the weight of your next test. Average is weighted average, which means we need to know what percent of the total grade your "next test" is.

For example, if your instructor gives three tests and two of them are 25% of the final grade and one is 50% of the final grade, your grade average for the term would be .25*first test grade + .25*second test grade + .50*final test grade = average grade for the term/semester.

Thus, in this case, we'd have .50*81 + .50*final test grade = 70; so that, .50*final test grade = 70 - 40.5 = 29.5 and final test grade = 29.5/.5 = 59 to end up with a 70 for the term. The .50*81 comes from the fact that with 50% of the grades in, you are carrying an 81 score. Which means you must have a 59 for the remaining 50% of the grades.

You can check your answer by simply putting your result into the weighted average equation. For example, with my numbers, we have .5*81 + .5*59 = ? = 40.5 + 29.5 = 70, which is the desired result for the term.

Now you need to do a weighted average using the real weights for each exam taken during the term. Remember the weights must add up to 1.00 or 100%.

Answer 3

Okay, here we go...

You have an 81 (assuming its only one test). Youy have another test but you want your average to be at lest a 70.

Take (81+x)/2, [the formula for averages] and you need it to be 70 so set that equation equal to 70. Divide both sides by 2 and you get...

81 + x = 140

Subtract 81 from both sides and you get...

59!!!
So you need to get a 59 to come out with a 70 average

Answer 4

Let's suppose there are a total of n tests, and let x be the score on your last test. Your average is:

[(n-1)*81 + x]/n = 70
Now solve for x.
81n - 81 + x = 70n
x = 70n - 81n + 81
x = 81 - 11n

So you need a score of at least 81 - 11*n, where n is the total number of tests.

Answer 5

a lot depends on the weighting that one exam has over and above the others