How to Find Time in Simple Interest

Formula:
t = I / Pr
Where: t = time in years, r = interest rate, I =simple interest, P = principal

Learn how to calculate time in simple interest with the following examples:

Question 1:
How long would it take for a principal of $220,000 to earn an interest of $23,100 at a rate of 3.5 percent per year?
Solution:
t = I / Pr = 23,100 / (220,000 * 0.035) = 23,100 / 7700 = 3
Thus, it would take 3 years.

Question 2:
Alfred borrowed $40,000 at a rate of 5% per annum. The amount owing at the end of the period was $55,000. For how long was the sum borrowed?
Solution:
I = 55,000 - 40,000 = $15,000
t = I / Pr = 15,000 / (40,000 * 0.05) = 15,000 / 2,000 = 7.5 years
The sum was borrowed for 7.5 years.

* Next: How to Find Simple Interest Rate

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Kelvin Wong Loke Yuen is a highly experienced education writer. He has obtained many certifications from the UK, USA, Australia and Canada, including an MBA and a Postgraduate Diploma from Heriot-Watt (UK's World-Class University) and a BCom degree from Adelaide (Australia’s Group of Eight University). Follow him on: LinkedIn