Exact Form : -53/12
Decimal Form : -4.416
Mixed numbers : -4 5/12
Why not look up "standard deviation" yourself, to be sure? But yes, the std. dev. is the sqrt of the variance.
Alright.
So let's say the number of adults is x.
Therefore, the number of boys is 7x + 1.
And then the total amount of girls is 3.5x + 0.5
So then:
x + 7x + 1 + 3.5x + 0.5 = 82
11.5x + 1.5 = 82
11.5x = 80.5
x = 7
So now we can figure out the number of male and female students.
Male students = 7x + 1
7*7 + 1
49 + 1
50
Male Students = 50
Female students = half of 50
50/2 = 25
Female Students = 25