What sum will fetch a simple interest of `25,410 in five and a half years at 6% p.a. rate of interest?

77000

since simple interest is additive and the same each year, therefore we can simply multiply time with interest that is 5.5 * 6%= 33%of the principal, which is the total interest earned for the time period which is given as 25410 therefore 25410/33*100%= principal