Ashok lent out ₹ 7,000 at 6% and ₹ 9,500 at 5%. Find his total income from the interest in 3 years.

Raj borrows ₹ 8,000; out of which ₹ 4,500 at 5% and the remaining at 6%. Find the total interest paid by him in 4 years.

A sum of money triples itself in 20 years. The rate of interest is:

1. 20%

2. 10%

3. 5%

4. 15%

A sum of money earns simple interest equal to 0.5 times the sum in 10 years; the rate of interest per annum is :

1. 20%

2. 10%

3. 5%

4. none of these