He paid 6.99 because each pound cost 0.99
For every boy, there are two girls. The ratio is 2:1 for girls to boys.
Answer:
The expected number of floors the elevator stops at, not counting the ground floor is =
n*(1-(1-1/n)^m)
Step-by-step explanation:
Here, we want to know the expected number of floors the elevator stops at.
let X1,X2,X3,..Xn are indicator variable for which value =1 if at least one person stops on that floor otherwise value is 0
P(at least one person stops at floor Xj)=1-P(none of m people stops at floor j)
=1-(1-1/n)^m
here total number of floors on elevetor Stops X=X1+X2+X3+...+Xn
hence expected number of floors on elevetor Stops
E(X)=E(X1)+E(X2)+E(X3)...+E(Xn)
=(1-(1-1/n)^m )+(1-(1-1/n)^m )+(1-(1-1/n)^m )+(1-(1-1/n)^m )+..... n times
=n*(1-(1-1/n)^m)
That would be the solution of the equation 1/8 = 6 / x
x = 6*8 = 48
Answer 48 trials
The solution to this problem is 0.77. You can find this answer through a math trick that always works. You should subtract the smaller absolute value from the larger absolute value of each number, and then reverse the operation if the larger absolute value is not the one you are subtracting from. In this case, I subtracted .14 from .91, and then made it negative because .91 was had the greater absolute value.
