If Suresh borrows Rs. 36000 from Mahesh at rate of interest 6% S.I, at the end of four years how much interest Suresh has to pay along with principal amount?

Sapna borrowed a certain sum of money from Kavita under the following repayment scheme based on simple interest. 8% p.a. for the initial 2 years, 9.5% p.a. for the next 4 years, 11% p.a. for the next 2 years, 12% p.a. after the first 8 years. Find the amount which a sum of Rs. 9000 taken for 12 years becomes at the end of 12 years?

Ajay bought Rs.11,000 from a bank to buy a car at 12% simple Interest. If he paid Rs 6,600 as interest while clearing the loan, find the time for which the loan was given.

Rakesh invests Rs. 8000 at some rate of interest. Being simple interest the  money doubles in 5 years. Raj sees this and invests Rs. 6250 for 3 years at the same rate of interest. How much interest does Raj get?

A certain sum becomes Rs 840 in 3 years and Rs 1200 in 7 years at simple interest. What is the value (in Rs) of principal? 

Ankur borrowed sum money from Megha at 8 % P.a simple interest and twice the amount from Harshita at 9 % P.a simple interest. He then added some more money of his own and lent the entire amount to Shalini at 10 % p.a simple interest. At the end of the year Ankur gained 14,000. If Ankur lend ₹ 40,000 to Shalini, then how much did Ankur borrow from Megha ? 

Ratio of the principal and the amount after 5 year is 10:12. Then the rate of interest per annum is