Since it was compounded monthly, we would apply the formula for calculating compound interest which is expressed as
A = P(1 + r/n)^nt
where
A is the amount after t years
P is the initial amount or principal
r is the interest rate
n is the number of compounding periods in a year
t is the time in years
From the information given,
A = 17000
r = 4.5/100 = 0.045
n = 12 because it was compounded monthly
t = number of days between April 21 and July 25 = 95 days
Recall,
365 days = 1 year
95 days = 95/365 = 0.26
Substituting these values into the formula, we have
17000 = P(1 + 0.045/12)^12 x 0.26
17000 = P(1.00375)^3.12
P = 17000/(1.00375)^3.12
P = 16802.63
Principal = $16802.63