Answer:
20 years
Step-by-step explanation:
We can find the time it took to invest
Using the formula for calculating simple interest as shown
SI = PRT/100
Given
Principal P = $600,000
SI = $39,000
Rate R = 3 1/4%
Required
Time
Substitute
39,000 = 600,000*13/400 * T
39,000 * 400 = 600,000*13 * T
15,600,000 = 7,800,000T
T = 15,600,000/7,800,000
T = 20
Hence it took 20years for the sum invested to generate the interest
