The Correct question is: At what rate of simple interest per annum will amount 10000 to Rs 12100 in 3 years.

Gicven Amount = 12100

Sum = 10000

Time = 3 years

Let rate of interest = r% per annum

Now, Simple Interest = Amount - Sum

                                  = 12100 - 10000

                                  = 2100

Again, Simple Interest = (Sum*Time*Rate of interest)/100

=> 2100 = (10000 * 3 * r)/100

=> 2100 = 100 * 3 * r

=> 2100 = 300r

=> r = 2100/300

=> r = 7

So, the rate of interest is 7% per annum.