Current account balance of Sonya = $1,533.43.
Initial deposited amount = $962.
Interest earned = Current Balance -Initial deposite = 1,533.43-962= $571.43.
Given interest rate = 3.3% per year.
3.3% could be convert in decimal form as 3.3/100= 0.033.
Let us assume number of years Sonya had account=t years.
Simple interest formula is given by
I=P*R*T, where P is the initial deposited amount, R is the rate of interest, T is the time in years and I is the inetrest earned.
Plugging value of I, P and R in the above formula, we get
571.43 = 962 * 0.033 * t
571.43 = 31.746t
Dividing both sides by 31.746, we get
571.43/31.746 = 31.746t/31.746
t=18 years.
Therefore, Sonya held the account for 18 years.
