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BACK 1.Find the present worth of Rs.930 due 3 years hence at 8% per annum.Aso find the discount? Sol: Amount=RS.930,Time=3years,Rate=8% TrueDiscount = (Presentworth*Time*Rate)/100 Presentworth = (Amount*100) /(100+(R*T)) Presentworth = (930*100)/(100+(8*3) =Rs.750 TrueDiscount = (930*3*8)/(100+(8*3)) =Rs.180 (or) TrueDiscount = Amount-Presentworth =Rs.930-Rs.750 =Rs.180 2.The truediscount on a bill due 9 months hence at 12% per annum is Rs540.Find the amount of the bill and its presentworth? Sol: Time=9months=9/12years=3/4years Rate=12% TrueDiscount=Rs540 TrueDiscount=(Amount*100)/(100+(R*T)) =>Amount=(TrueDiscount*(100+(R*T))) /100 =(540*(100+12*(3/4))/100 =Rs.6540 Presentworth=Amount-TrueDiscount =Rs.6540-Rs540 =Rs.6000 3.The TrueDiscount on a certain sum of money due 3 years hence is Rs.250 and SimpeInterest on the same sum for same time and same rate is Rs375 find sum and rate%? Sol: Time=3 years Truediscount=Rs.250 SimpeInterest=Rs375 Sum = (SimpeInterest*TrueDiscount)/(SimpeInterest-TrueDiscount) = (375*250)/(375-250) =Rs.750 SimpeInterest=(Principle*Time*Rate)/100 375 = ( 750*3R)/100 R=50/3% => Rate=162/3% 4.The difference between SimpeInterest and TrueDiscount on a certain sum of money for 6 months at 121/2% per annum is Rs25.find the sum. Sol: Let amount be Rs.x SimpleInterest=(Amount*T*R)/100 TrueDiscount=(Amount*T*R)/(100+(R*T)) SI-T.D=Rs25 =>((x*6/12*25/2)/100)-((x*6/12*25/2)/(100+(6/12*25/2))=25 =>x=Rs.6800 5.The Present worth of Rs.2310 due 21/2yrs henceThe interest being 15% per annum is sol: Amount=Rs2310,Time=21/2yrs,Rate=15% Presentworth = (Amount*100) /(100+(R*T)) =2310*100/(100+15*5/2) =Rs1680. BACK |