A sum of ₹x amounts to ₹54571 in 2 1/2 years at 12% p.a., interest compounded after every 10 months. What is the value of x?

Varun invests a sum of ₹5400 and Ashish invests a sum of ₹9400 at the same rate of simple interest per annum. If, at the end of 3 years, Ashish gets ₹960 more interest than Varun, then find the rate of interest per annum (in percentage).