What annual payment will discharge a debt of Rs.7620 due in 3years at 1623 % per annum interest?

Let each installment be Rs.x. Then, 

(P.W. of Rs.x due 1 year hence) + (P.W of Rs.x due 2 years hence) + (P.W of Rs. X due 3 years hence) = 7620.

$\frac{x}{1+\frac{50}{3x100}}+\frac{x}{1 +\frac{50}{3x100}2}+\frac{x}{1} = 7620$

  $\frac{6x}{7}+\frac{36x}{49}+\frac{216x}{343}=7620$

  $294x + 252x + 216x = 7620 x 343$

 => x = 3430

 Amount of each installment = Rs.3430