# 17: Banker's discount¶

## Example number 17.1, Page number 17.2¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
P=2550;    #principal(Rs)
R=8;       #rate(%)
T=3/12;       #time(yrs)

#Calculation
TD=P*R*T/(100+(R*T));    #true discount(Rs)
BD=P*R*T/100;        #banker's discount(Rs)
BG=BD-TD;     #banker's gain(Re)

#Result
print "true discount is",TD,"Rs"
print "banker's discount is",BD,"Rs"
print "banker's gain is",BG,"Re"

true discount is 50.0 Rs
banker's discount is 51.0 Rs
banker's gain is 1.0 Re


## Example number 17.2, Page number 17.2¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
R=6;       #rate(%)
T=11/12;       #time(yrs)
BD=58.025;        #banker's discount(Rs)

#Calculation
P=BD*100/(R*T);    #principal(Rs)

#Result
print "principal is",P,"Rs"
print "answer given in the book is wrong"

principal is 1055.0 Rs
answer given in the book is wrong


## Example number 17.3, Page number 17.2¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
R=4;       #rate(%)
T=9/12;       #time(yrs)
TD=20;    #true discount(Rs)

#Calculation
BD=TD*(1+(R*T/100));        #banker's discount(Rs)

#Result
print "banker's discount is",BD,"Rs"

banker's discount is 20.6 Rs


## Example number 17.4, Page number 17.3¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
R=3;       #rate(%)
T=2;       #time(yrs)
TD=50;    #true discount(Rs)

#Calculation
BG=TD*R*T/100;     #banker's gain(Rs)

#Result
print "banker's gain is",BG,"Rs"

banker's gain is 3.0 Rs


## Example number 17.5, Page number 17.3¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
P1=1000;     #principal(Rs)
P2=1050;     #principal(Rs)
R=5;      #rate(%)

#Calculation
T=((P2*R*100/(P1*R))-100)/R;      #time(yrs)

#Result
print "time is",T,"yr"

time is 1.0 yr


## Example number 17.6, Page number 17.3¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
TD=90;    #true discount(Rs)
P=540;     #principal(Rs)

#Calculation
BD=((TD**2)/(P-TD))+TD;     #banker's discount(Rs)

#Result
print "banker's discount is",BD,"Rs"

banker's discount is 108.0 Rs


## Example number 17.7, Page number 17.3¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
R=5;       #rate(%)
T=2;       #time(yrs)
BG=15;     #banker's gain(Rs)

#Calculation
P=BG*100*(100+(R*T))/((R*T)**2);     #principal(Rs)

#Result
print "principal is",P,"Rs"

principal is 1650.0 Rs


## Example number 17.8, Page number 17.3¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
R=2;       #rate(%)
T=5;       #time(yrs)
BG=20;     #banker's gain(Rs)

#Calculation
PW=BG*(100**2)/((R*T)**2);     #present worth of bill(Rs)

#Result
print "present worth of bill is",PW,"Rs"

present worth of bill is 2000.0 Rs


## Example number 17.9, Page number 17.3¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
BG=25;     #banker's gain(Rs)
PW=10000;     #present worth of bill(Rs)

#Calculation
TD=math.sqrt(PW*BG);    #true discount(Rs)

#Result
print "true discount is",TD,"Rs"

true discount is 500.0 Rs


## Example number 17.10, Page number 17.3¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
BD=40;    #banker's discount(Rs)
TD=30;    #true discount(Rs)

#Calculation
P=BD*TD/(BD-TD);      #sum(Rs)

#Result
print "sum is",P,"Rs"
print "answer given in the book is wrong"

sum is 120.0 Rs
answer given in the book is wrong


## Example number 17.11, Page number 17.4¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
BD=1;      #assume
BG=(7/57)*BD;    #banker's gain(Rs)
T=2;       #time(yrs)

#Calculation
R=BG*100/((BD-BG)*T);     #rate(%)

#Result
print "rate is",R,"%"

rate is 7.0 %


## Example number 17.12, Page number 17.4¶

In :
#importing modules
import math
from __future__ import division

#Variable declaration
BDbyTD=21/20;       #ratio of BD and TD
T=5/2;       #time(yrs)

#Calculation
R=(BDbyTD-1)*100/T;     #rate(%)

#Result
print "rate is",R,"%"

rate is 2.0 %