The following question are accompanied by two statements i.e. statement (I) and statement (II). You have to determine which statement (s) is/are sufficient/necessary to answer the question.

What is the principal amount (in Rs) ?
Statement I. The simple interest on the principal amount after 3 years is equal to 30% of the principal.
Statement II. The compound interest on the principal amount for 2 years at an annual interest rate of 10%, compounded annually is Rs 630.

Correct option is B

Statement I. Let the principal amount be Rs 100a
And rate of interest be R%
ATQ,

This does not directly give us the principal amount .
Statement II. Cumulative interest rate =

Principal amount =

So, Statement II alone.