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Simple interest calculator

Simple interest is calculated solely on the amount initially invested. This calculator can help you deal with many different kinds of simple interest problems. The calculator prints an easy-to-follow, step-by-step explanation.

problem

You deposit $1000 into a bank account and received $50 simple interest after 3 months. What had been the interest rate?

solution

The interest rate was 20% per year.

explanation

STEP 1: Convert 3 months into years.

$$ \text{ 3 months } = \frac{ 3 }{12} \text{ years} = 0.25 \text{ years}$$

STEP 2: Find the interest rate by using the formula $ I = P \cdot i \cdot t $, where I is interest, P is total principal, i is rate of interest per year, and t is total time in years.

In this example I = $50, P = $1000 and t = 0.25 years, so

$$ \begin{aligned} I &= P \cdot i \cdot t \\ i &= \frac{I}{P \cdot t} \\ i &= \frac{ 50 }{ 1000 \cdot 0.25} \\ i &= 0.2 = 20\% \text{ per year} \end{aligned}$$

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Simple Interest Calculator
Find the amount of money you receive after investing time.
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Simple Interest Calculator
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Examples:
example 1:ex 1:
You put $1,000 into a bank account that pays 7% simple interest each year. You left the money in there for 3 years. Determine the interest earned and the total amount at the end of three years.
example 2:ex 2:
You deposit $12000 into a bank account with a monthly interest rate of 1.5%. You had the money in there for $210 days. Determine the amount of interest earned.
example 3:ex 3:
You put money into a bank account that pays 4% simple interest each year. After three years, you collected $72 in interest. How much was the deposit (principal)?
example 4:ex 4:
You put money into a bank account that pays 2% simple interest every six months. After 9 months, you received $15 in interest. How much was the principal?
example 5:ex 5:
You deposited $1000 into a bank account and received $50 in simple interest after three months. What was the interest rate?
example 6:ex 6:
You deposit $350 into a bank account with a monthly interest rate of 1.2%. Determine the length of time the money was in the bank if you received $9 in interest.
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