PLEASE HELP This graph shows the results of 100 test takers.

The mean of the scores was 70
The minimum was 40
The maximum was 100
The standard deviation was 5
How many students scored within 1 Standard Deviation of the mean?

Can someone explain the elimination method to me for this problem?

After the seventh month of a 12-month loan: the numerator is: {(n + 11) + (n + 10) + (n + 9) + (n + 8) + (n + 7) + (n + 6) + (n + 5)} = , and the denominator is: {(n) + (n + 1) + + (n + 11)} = . therefore, the fraction is numerator/denominator (to the nearest tenth) = %

There were 816 people at a concert when a band started to play. after each song, only half the people stayed to hear the next song. how many people were left at the concert after x songs? write a function to represent this scenario.