Find the principal which yields a simple interest of Rs. 20 and compound interest of Rs. 30 in two years, at the same percent rate per annum?  Choose the correct choice from the following choices
A) s. 20  B) s. 48  C) s. 42  D) s. 20  E) s. 60
Explanation:   SI in 2 years = Rs. 20, SI in 1 year = Rs. 10   CI in 2 years = Rs. 30   % rate per annum = [(CI – SI) / (SI in 1 year)] *100   = [(30 – 20) / 20] * 100   = 50 % p.a.   Let the principal be Rs. X   Time = T = 2 years   % rate = 50% p.a.   SI = (PRT/100)   20 = (X*50*2) / 100   X = Rs. 20   s. 20NSWER: s. 20
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Find the principal which yields a simple interest of Rs. 20 and compound interest of Rs. 30 in two years, at the same percent rate per annum?