Certain sum becomes 3 times it self at compound interest in 10 years. In how many years it becomes 9 times?
Choose the correct option.
A) 10 Years	B) 20 Years	C) 30 Years	D) 40 Years	E) 45 Years
P(1 + R/100)10 = 3P   =&gt; P(1 + R/100)10 = 3   Let P(1 + R/100)n = 9P   =&gt; (1 + R/100)n = 9   =&gt; 32 = [(1 + R/100)10]2   =&gt; (1 + R/100)n =&gt; (1 + R/100)20   =&gt; n = 20 Years.   20 Years
<result>B</result>
Certain sum becomes 3 times it self at compound interest in 10 years. In how many years it becomes 9 times?