We can solve for the initial amount using the simple interest formula:
Simple Interest = (Principal x Rate x Time) / 100
Where:
Simple Interest = R320
Rate = 12% per year
Time = 9/12 years (9 months is 3/4 of a year)
Substituting the given values:
R320 = (Principal x 12 x 3/4) / 100
Multiplying both sides by 100 and dividing by 12 x 3/4:
R320 x 4 x 100 / 12 x 3 = Principal
Simplifying the fraction:
R320 x 400 / 36 = Principal
R320 x 100 / 9 = Principal
Principal = R3,555.56 (rounded to the nearest cent)
Therefore, the initial amount is R3,555.56 if you earn interest of R320 in 9 months at a simple interest rate of 12% per year.
What is the initial amount if you earn interest of R320 in 9 months at a simple interest rate of 12% per year
3 answers
At what annual simple interstate rate should 96 be invested for 5 months, so as to produce the same interest earned if 75 was invested at 10% per annum for 1 year?
We can start by calculating the interest earned on the second investment of R75 at a simple interest rate of 10% per annum for 1 year.
Simple Interest = (Principal × Rate × Time) / 100
Simple Interest = (R75 × 10% × 1) / 100
Simple Interest = R7.50
Now we need to find the annual simple interest rate, r, for an investment of R96 for 5 months (which is equivalent to 5/12 of a year) that will produce the same interest earned of R7.50.
Simple Interest = (Principal × Rate × Time) / 100
R7.50 = (R96 × r × 5/12) / 100
R7.50 = R4r / 5
r = (5 × R7.50) / R4
r = 18.75%
Therefore, an annual simple interest rate of 18.75% is required for an investment of R96 for 5 months to produce the same interest earned as an investment of R75 at 10% per annum for 1 year.
Simple Interest = (Principal × Rate × Time) / 100
Simple Interest = (R75 × 10% × 1) / 100
Simple Interest = R7.50
Now we need to find the annual simple interest rate, r, for an investment of R96 for 5 months (which is equivalent to 5/12 of a year) that will produce the same interest earned of R7.50.
Simple Interest = (Principal × Rate × Time) / 100
R7.50 = (R96 × r × 5/12) / 100
R7.50 = R4r / 5
r = (5 × R7.50) / R4
r = 18.75%
Therefore, an annual simple interest rate of 18.75% is required for an investment of R96 for 5 months to produce the same interest earned as an investment of R75 at 10% per annum for 1 year.
3 answers