Question

a sum of money lent at simple interest amounts to Rs 4745 in 3 yrs and to Rs 5475 in 5 yrs. find the sum and rate percent per annum.

Answer 1

let sum is p and rate is r
SI=4745-p in 3 years -----------(1)
SI=5475 -p in 5 years ---------(2)
subtracting (2) to (1)
SI=730 in 2 years
hence 1 year SI = 365 Rs
hence 3 years Si=3 x 365= 1095 Rs
now put Si in equation (1)
1095=4745-p
p=4745-1095=3650 Rs
hence sum =3650 Rs
now
Si=p x r x t/100

1095=3650 x r x 3/100

r=10%

Answer 2

let sum is p and rate is r
SI=4745-p in 3 years -----------(1)
SI=5475 -p in 5 years ---------(2)
subtracting (2) to (1)
SI=730 in 2 years
hence 1 year SI = 365 Rs
hence 3 years Si=3 x 365= 1095 Rs
now put Si in equation (1)
1095=4745-p
p=4745-1095=3650 Rs
hence sum =3650 Rs
now
Si=p x r x t/100

1095=3650 x r x 3/100

r=10%