7. Calculate the simple interest on R1 200 ot \( S I=\frac{P r I}{100} \) \( (P= \) principal amount, \( t= \) time (number of \( y \) simple interest). 8. How long will it take for R6 000 invested at \( 6 \% \) per annum simple in grow to \( R 8520 \) ? (Use the formula \( S I=\frac{P r i}{100} \) ) 9. Temoso borrowed R1 000 from the bank for 3 years at \( 8 \% \) compound Without using a formula, calculate how much Temoso owes the ban end of three years. 10. Tom pays \( R 1250 \) rent every month. What is his annual rent? If his rent is by \( 8,5 \% \) at the end of the year, what will his increased monthly rent be?

Alright, I need to solve these four financial problems step by step. Let's tackle them one by one. **Problem 7: Calculate the simple interest on R1 200.** The formula for simple interest is: \[ S I = \frac{P \times r \times t}{100} \] Where: - \( P \) is the principal amount, - \( r \) is the rate of interest per annum, - \( t \) is the time in years. Given: - \( P = R1,200 \) - \( r = ? \) (not provided) - \( t = ? \) (not provided) Wait, the problem doesn't provide the rate of interest (\( r \)) or the time (\( t \)). Without these values, I can't calculate the simple interest. Maybe I missed something. Let me read the question again. Oh, I see. The problem only provides the principal amount but not the rate or time. Since both \( r \) and \( t \) are missing, it's impossible to compute the simple interest. Perhaps there's an assumption that \( r \) and \( t \) are standard values, but without explicit numbers, I can't proceed. Maybe I should consider common rates and times, but that would be speculative. Alternatively, maybe the problem expects me to express the simple interest in terms of \( r \) and \( t \). Let's try that. \[ S I = \frac{1,200 \times r \times t}{100} \] \[ S I = 12 \times r \times t \] So, the simple interest is 12 times the rate multiplied by the time. But this doesn't give a numerical value. I think the problem might be incomplete or missing some information. **Problem 8: How long will it take for R6 000 invested at 6% per annum simple interest to grow to R8,520?** Using the simple interest formula: \[ S I = \frac{P \times r \times t}{100} \] Where: - \( P = R6,000 \) - \( r = 6\% \) - \( S I = R8,520 - R6,000 = R2,520 \) (since the total amount after interest is R8,520) Plugging in the values: \[ 2,520 = \frac{6,000 \times 6 \times t}{100} \] \[ 2,520 = \frac{36,000 \times t}{100} \] \[ 2,520 = 360 \times t \] \[ t = \frac{2,520}{360} \] \[ t = 7 \text{ years} \] So, it will take 7 years for the investment to grow from R6,000 to R8,520 at a 6% simple interest rate. **Problem 9: Temoso borrowed R1,000 from the bank for 3 years at 8% compound interest. Without using a formula, calculate how much Temoso owes the bank at the end of three years.** Compound interest means the interest is calculated on both the principal and the accumulated interest from previous periods. Without a formula, I'll have to calculate it step by step. First year: - Principal: R1,000 - Interest: \( 1,000 \times 8\% = R80 \) - Total after first year: \( 1,000 + 80 = R1,080 \) Second year: - Principal: R1,080 - Interest: \( 1,080 \times 8\% = R86.40 \) - Total after second year: \( 1,080 + 86.40 = R1,166.40 \) Third year: - Principal: R1,166.40 - Interest: \( 1,166.40 \times 8\% = R93.312 \) - Total after third year: \( 1,166.40 + 93.312 = R1,259.712 \) Rounding to two decimal places, Temoso owes the bank R1,259.71 at the end of three years. **Problem 10: Tom pays R1,250 rent every month. What is his annual rent? If his rent is increased by 8.5% at the end of the year, what will his increased monthly rent be?** First, calculate the annual rent: - Monthly rent: R1,250 - Number of months in a year: 12 - Annual rent: \( 1,250 \times 12 = R15,000 \) Next, calculate the increased monthly rent after an 8.5% increase: - Current monthly rent: R1,250 - Increase: \( 1,250 \times 8.5\% = R106.25 \) - New monthly rent: \( 1,250 + 106.25 = R1,356.25 \) So, Tom's annual rent is R15,000, and his increased monthly rent after an 8.5% hike is R1,356.25.