The bankers discount and the true discount of a sum at 20% per annum simple interest for the same time are Rs.80 and Rs.40 respectively. What is the sum and the time?
Choose one
A) Sum = Rs.80 and Time = 5 years B) Sum = Rs.100and Time = 5 years C) Sum = Rs.60 and Time = 5 years D) Sum = Rs.120 and Time = 5 years E) None of these
Explanation :   BD = Rs.80   TD = Rs.40   R = 10%   F = BD ×TD/(BD – TD)=80×40/(80–40)=80×40/40=Rs. 80   BD = Simple Interest on the face value of the bill for unexpired time =FTR/100   ⇒80= (80×T×20)/100   ⇒80 = 8 × T × 2 ⇒10= 2 × T   ⇒ T = 10/2= 
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5 years Sum= Rs.80 and Time = 5 yearsnswer : Option Sum = Rs.80 and Time = 5 years
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The bankers discount and the true discount of a sum at 20% per annum simple interest for the same time are Rs.80 and Rs.40 respectively. What is the sum and the time?