Simple Interest - General Questions

A sum of Rs. 7,000 becomes 4 times itself in 5 years at simple interest. What is the rate of interest?

A sum of Rs. 18,000 earns a simple interest of Rs. 10,800 in 6 years. What is the rate of interest per annum?

A sum of Rs. 12,000 earns a simple interest of Rs. 2,880 in 3 years. What is the rate of interest per annum?

A sum of money amounts to Rs. 6,240 in 2 years and to Rs. 8,320 in 6 years at simple interest. What is the sum?

In how many years will a sum of money double itself at 20% per annum simple interest?