Question 231 of 480
If the interest on N150.00 for 21/2 years is N4.50, find the interest on N250.00 for 6 months at the same rate
- A. N1.50
- B. N7.50
- C. N15.00
- D. N18.00
Correct Answer:
A
Explanation
To solve the problem, we need to determine the interest on N250.00 for 6 months, given that the interest on N150.00 for 2.5 years is N4.50. We will follow these steps:
### Step 1: Calculate the Interest Rate
First, we need to find the interest rate from the information provided. We know:
- Principal (P) = N150.00
- Time (T) = 2.5 years
- Interest (I) = N4.50
The formula for simple interest is:
\[
I = P \times r \times T
\]
Where:
- \( I \) is the interest earned,
- \( P \) is the principal amount,
- \( r \) is the rate of interest per year (in decimal),
- \( T \) is the time in years.
Rearranging the formula to find the rate \( r \):
\[
r = \frac{I}{P \times T}
\]
Substituting the known values:
\[
r = \frac{4.50}{150 \times 2.5}
\]
Calculating the denominator:
\[
150 \times 2.5 = 375
\]
Now substituting back into the equation for \( r \):
\[
r = \frac{4.50}{375} = 0.012
\]
To express this as a percentage, we multiply by 100:
\[
r = 0.012 \times 100 = 1.2\%
\]
### Step 2: Calculate the Interest for N250.00 for 6 Months
Now that we have the interest rate, we can calculate the interest on N250.00 for 6 months.
First, we need to convert 6 months into years:
\[
T = \frac{6}{12} = 0.5 \text{ years}
\]
Now we can use the simple interest formula again:
\[
I = P \times r \times T
\]
Where:
- \( P = N250.00 \)
- \( r = 0.012 \) (from our previous calculation)
- \( T = 0.5 \)
Substituting these values into the formula:
\[
I = 250 \times 0.012 \times 0.5
\]
Calculating the interest:
\[
I = 250 \times 0.012 = 3.00
\]
\[
I = 3.00 \times 0.5 = 1.50
\]
### Final Answer
The interest on N250.00 for 6 months at the same rate is **N1.50**.
### Explanation of Other Options
- **Option B (N7.50)**: This amount is too high for the interest calculated based on the rate we derived. It does not align with the calculations we performed.
- **Option C (N15.00)**: This amount is also too high. It would imply a much higher interest rate or a longer time period than what we have.
- **Option D (N18.00)**: This is significantly higher than what we calculated. It suggests an unrealistic interest accumulation for the given principal and time.
### Revision Summary
- The interest rate was calculated from the initial conditions using the simple interest formula.
- The interest on N250.00 for 6 months was calculated using the same interest rate.
- The correct answer is N1.50, as derived from the calculations.
- Always ensure to convert time into years when using the simple interest formula.