Answer: It is because if ∠N and ∠K are congruent and are same in size and shape.
Our P = 100, r = .08, n = 1 (annually means once a year), and t = 15. Filling in accordingly, we have

. Simplifying a bit gives us

and

. Raising that number inside the parenthesis to the 15th power gives us

. Multiplying to finish means that A(t) = $317.22
6 boys, ratio is boy:girl 2:3
It would cost $132. 7+7+15+15X3=132