Compound Interest Q23

23. What is the rate of interest p.c.p.a.?

I.An amount doubles itself in 5 years on simple interest.

II. Difference between the compound interest and the simple interest earned on a certain amount in 2 years is Rs. 400.

 III. Simple interest earned per annum is Rs. 2000.

A.        I only

B.        II and III only

C.        All I, II and III

D.        Any two of the three

E.        I only or II and III only

Answer: Option E

Explanation:

I.	P x R x 5	= P            R = 20.
	100

II. P		1 +	R		2	- P -	P x R x 2	= 400          PR2 = 4000000.
			100				100

III.	P x R x 1	= 2000          PR = 200000.
	100

	PR2	=	4000000	R = 20.
	PR		200000

Thus I only or (II and III) give answer.

                        Correct answer is (E).