A basketball hoop is 10 feet off the floor
It's annuity problem
To solve your question use the formula of the present value of annuity ordinary which is
Pv=pmt [(1-(1+r)^(-n))÷r]
Pv present value?
PMT yearly payments 18000
R interest rate 0.09
N time 20 years
So
Pv=18,000×((1−(1+0.09)^(−20))÷(0.09))
pv=164,313.82
0.6 milliliters
(I'm not 100% positive, you might have to convert it...but it seems correct.)
A) x + y = -80
B) 3x = y
x + 3x = -80
4x = -80
x = -20
y = -60
