1. 

What is the sum which earned interest?

I. The total simple interest was ₹ 7000 after 7 years.

II. The total of sum and simple interest was double of the sum after 5 years.

A. I alone sufficient while II alone not sufficient to answer
B. II alone sufficient while I alone not sufficient to answer
C. Either I or II alone sufficient to answer
D. Both I and II are not sufficient to answer
E. Both I and II are necessary to answer

Answer: Option E

Explanation:

Let the sum be ₹x.

I gives, S.I. = ₹ 7000 and T = 7 years.

II gives, Sum + S.I. for 5 years = 2 x Sum    

    Sum = S.I. for 5 years.

Now, S.I. for 7 years = ₹ 7000.

S.I. for 1 year = Rs. 7000 = ₹ 1000.
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Thus, I and II both are needed to get the answer.

Correct answer is (E).