Answer: $15000
Explanation:
The formula to calculate the simple interest is given by :-
, where P is the principal amount , r is the rate of interest and t is the time period.
Given: Interest amount = $3,375
Rate of interest = 4.5%=0.045
Time period = 5 years
Let P be the principal amount, then we have

Hence, the principal amount of the account was $15000.