Find the compound interest on ₹64000 at 10% per annum for 9 months when interest is compounded quarterly.

₹4921

Principal = Rs. 64,000, Rate = 10% 

Time = 9 months, Condition = Quarterly 

Time = Time × 4, Rate = Rate/4 

Calculations:

New time = 1 × 9 months = 3 years 

New Rate = 10/4 = (5/2) % 

(5/2)% = 1/40 

Principal                    Amount

40                                        41

40                                       41

40                                       41

Total principal =          Total Amount =

40 × 40 × 40                41 × 41 × 41

= 64000                     = 68921

Interest = 68921 – 64000  = 4921

64000  = 64,000 ( Given)

then Interest = 4921 = 4921