Interest is charged on ₹120000 for first eight months at six percent and then on remaining ₹70000 for four months. What is total interest?

Correct answer: ₹6200

Interest for different periods must be calculated separately because both the principal amount and the applicable rate may change. For the first eight months, interest on ₹120000 at 6% per year is \\(120000\\times6\\times\\frac{8}{100\\times12}=₹4800\\). After that, the remaining principal is ₹70000. Interest on ₹70000 at 4% per year for four months is \\(70000\\times4\\times\\frac{4}{100\\times12}=₹1400\\).

Adding the two amounts gives total interest of \\(₹4800+₹1400=₹6200\\). Therefore, option A is correct. A common mistake is to apply one rate to the whole amount for all twelve months, even though the question gives two different periods and rates. The time fraction must be expressed in months divided by twelve because the rates are annual rates.