Question

Suppose you deposited ​$400 in a savings account 2 years ago. The simple interest rate is 3.4 %. The interest that you earned in those 2 years is ​$27.20. Which of the following​ is/are true?
t equals 400
Upper I equals 27.20
p equals 2
r equals 3.4 %
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Part 1
Which of the following​ is/are true? Select all that apply.
A.t equals 400
tequals400
B.p equals 2
pequals2
C.Upper I equals 27.20
Upper Iequals27.20
D.r equals 3.4 %
requals3.4 %

Answer 1

To determine which statements are true, let's define the variables involved in the simple interest formula:

The simple interest formula is:
\[ I = P \times r \times t \]

Where:
- \( I \) = interest earned
- \( P \) = principal amount (initial deposit)
- \( r \) = interest rate (as a decimal)
- \( t \) = time in years

From the problem statement:
- You deposited $400, so \( P = 400 \).
- The interest earned is $27.20, so \( I = 27.20 \).
- The interest rate is 3.4%, which we can express as a decimal: \( r = \frac{3.4}{100} = 0.034 \).
- The time is given as 2 years, so \( t = 2 \).

Now, let's evaluate each statement:

A. **t equals 400**
- This is false. \( t \) represents time in years, which is 2, not 400.

B. **p equals 2**
- This is false. \( P \) (the principal) is $400, not 2.

C. **Upper I equals 27.20**
- This is true. The interest earned is given as $27.20.

D. **r equals 3.4 %**
- This is true. The interest rate is stated as 3.4%.

### Summary:
The true statements are:
- **C. Upper I equals 27.20**
- **D. r equals 3.4 %**