Correct Answer - Option 2 : Rs. 631.945

**Given: **

The Rate of interest is 20 %

The Installment is Rs. 300

Number of installment is 3

**Formula used:**

P( 1+ R/100)^{n }= X( 1+ R/100)^{n-1 } + X( 1+ R/100)^{n-2 } + X( 1+ R/100)^{n -3} + X( 1+ R/100)^{n-4} + ----

Where,

P = principal

R = Rate

n = number of installments

X = amount of installment

**Calculation:**

P(1 + 20/100)^{3} = 300(1+20/100)^{2} + 300(1 + 20/100)^{1}+ 300

⇒ P(1.2)^{3} = 300 × 1.44 + 300 × 1.2 + 300

⇒ P(1.2)^{3} = 432 + 360 + 300

⇒ P = 631.945

**∴ The sum is Rs. 631.95.**