Aprofessor has recorded exam grades for 20 students in his class, but one of the grades is no longer readable. if the mean score on the exam was 81 and the mean of the 19 readable scores is 85, what is the value of the unreadable score?

The value of the unreadable score is

It should be noted that the mean of numbers simply means the average of the numbers.

Since the mean score of the 20 students was 81, then the total score will be:

Then, since the mean score of the 19 students was 85, their total scores will be: =

The value of the unreadable score will be:

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d) by the cross product property, ab^2 = bc multiplied by ad

step-by-step explanation:

we are given

in the given triangle abc

angle a is 90° and segment ad is perpendicular to segment bc

we can see that

triangle(abc) and triangle(abd) are similar because they have common side and same angle (90 degree)

so, triangles(abc) and abd are similar

since, they are similar

so, the ratio of their sides must be equal

we get

now, we can cross multiply

and we get

so, this could be step to prove it

won't that be plagrisim thought?

step-by-step explanation: