A sum lent at simple interest amounts to ₹6,240.80 in one year and to ₹7,563.20 in 4 years. The sum (in ₹) and the rate of interest per annum, respectively, are:

5,800, 7.6%

SI of ( 4 - 1 ) years = 7563.20 - 6240.80 = 1322.4

Si of 1 year  = 1322.4 × \(\frac{1 }{3 }\) = 440.8

Now , Initial sum = 6240.80 - 440.8  = 5800

Simple Interest = \(\frac{Principal ×Rate × Time }{100}\)

440.8 = \(\frac{5800 × Rate × 1 }{100}\)

Rate = 7.6%

So , Initial sum = 5800 and Rate = 7.6%