Question

A certain sum of money at simple interest amounts to ₹ 1,300 in 4 years and to ₹1,525 in 7 years . find the sum of money Solve the whole sum

Answer 1

Let the sum of money be ₹x.
P=₹x
A=₹1300
T=4 yrs
Therefore,SI =A-P
=₹(1300-x)
R%pa=SI×100÷(P×T)
=₹(1300-x)×100÷(₹x×4).............(1)
Now, P=₹x
T=7yrs
A=₹1525
SI=A-P
0=₹(1525-x)
R%pa=SI×100÷(P×T)
=₹(1525-x)×100÷(₹x×7).........(2)

(1)and(2)
(1300-x)×100÷(x×4) = (1525-x)×100÷(x×7)
that implies,(1300-x)÷4 =(1525-x)÷7
". 7(1300-x) = 4(1525-x)
". 9100-7x = 6100-4x
". -7x +4x = 6100-9100
". -3x = - 3000
". x = 3000÷3
". x = 1000
therefore, the sum of money=₹1000