An amount doubles itself in 5 years with simple interest. What is the rate of interest per year?

A sum of ₹ 1750 is divided into two parts such that the interests on the first part at 8 % simple interest per annum and that on the other part at 6 % simple interest per annum are equal. The interest on each part (in rupees) is 

If certain sum, at simple interest turns into thrice of actual amount in 4 years. Find out time to become the amount thirteen times of initial amount? 

The difference between the simple interest between the simple interest received from two different sources on ₹ 1500 for 3 years is ₹ 13.50. The difference between their rate of interest is - 

A sum of ₹ 7, 930 is divided into 3 parts and given at loan at 5 % simple interest to A, B and C for 2, 3 and 4 years respectively. If the amounts of all three are equal after their respective periods of loan, then the A received a loan of 

The simple interest for four years is one fourth of the principal. At the same rate, which amount become Rs.450 total amount in 2 years?

A sum of Rs. 400 becomes Rs. 448 at simple interest in 2 years. In how many years, will the sum of Rs. 550 amounts to Rs. 682 at the same rate?