If a sum of money trebles itself in 40 years,what is the rate of interest? Pick:	A) 5%	B) 6%	C) 4%	D) 3%	E) None of these
Explanation:   Let the sum of money be Rs.x   5%fter 40 years, this becomes 3x   Simple Interest = 3x - x = 2x   Simple Interest = PRT/100   2x = (x×R×40)/100   2 = (R×40)/100   200 = 40R   R = 5%   5%nswer: Option 5%
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If a sum of money trebles itself in 40 years,what is the rate of interest?