To calculate the simple interest, we use the formula:

$I = P \times r \times t$

Where:

• $P = 840$ (Principal amount)
• $r = 9\% = 0.09$ (Annual interest rate)
• $t = 6$ months $= \frac{6}{12} = 0.5$ years

$I = 840 \times 0.09 \times 0.5$

$I = 37.80$

Total Amount (A)

$A = P + I = 840 + 37.80 = 877.80$

Final Answer

• Interest earned: $37.80
• Total amount after 6 months: $877.80

Would you like more details or have any questions?

Related Questions

1. How does compound interest compare to simple interest in this case?
2. What would the interest be if the time was 1 year instead of 6 months?
3. How much interest would accumulate in 2 years at the same rate?
4. How would the calculation change if the interest was compounded monthly?
5. What is the formula for continuous interest growth?

Tip:

Always convert the time to years when using the simple interest formula.