CBSE Class 9 Answered

Principal = 5000, Rate = 10% per annum, Time 1.5 yrs.

Now, it's compounded half yearly.

So if interest rate is 10% per annum, it's 5% per semiannually.

So compound interest is 5% per semiannually.

So amount at the end of half year = 5000 (1 + 0.05) = 5000(1.05) = 5250.

Now this amount is principal for next half year and so on.

So at the end of 1 yr = 5250x1.05 = 5512.5

and at the end of 1 and 1/2 year = 5512.5x1.05 = 5788.125

This can be calculated by simple formula.

Formula for calculating compound interest:

Where,

• P = principal amount (initial investment)
• r = annual nominal interest rate (as a decimal)
• n = number of times the interest is compounded per year
• t = number of years
• A = amount after time t

Using this we can directly calculate,

A = (5000)(1 + 0.10/2)^(1.5x2) = 5788.125

Similarly for second case,

A = (2000)(1 + 0.12/2)^(1x2) = 2247.2

Regards,

Team,

TopperLearning.