The mean is 30,000
The standard deviation is 10,893.42
What do you mean by a0 and a1?
Probability that nbr1 is a boy is p1 = 6/10.
Probability that nbr2 is a boy, given 5 boys left is 5/9
Probability that nbr3 is a boy given 4 boys left is 4/8
Probability that nbr 4 is a boy given 3 boys left is 3/7
Approximately 0.071 or 7.1%
Opposite of 90* would be equivalent to the square root of the other sides
t = 3 years
the formula for calculating simple interest (I ) is
I = 
multiply both sides by 100
PRT = 100I
divide both sides by PR
T =
=
=
= 3