The formula for determining simple interest is expressed as
I = PRT/100
Where
I = interest earned
P = principal or amount deposited
R = interest rate
T = time or duration in years
From the information given,
P = 2500
R = 8.5
If the total amount after t years is 4625, then the interest earned is
4625 - 2500 = 2125
This means that I = 2125
Thus, we have
2125 = (2500 * 8.5 * T)/100
2125 = 212.5T
T = 2125/212.5
T = 10
The number of years is 10