Question

a money lender lent rs.1000 at 3% per year and rs.1400 at 5% per year. the amount should be returned to him when the total interest comes to rs.350. find the number of years.

Answer 1

a money lender lent Rs. 1000 at 3% per year and Rs. 1400 at 5% per year the amount should be returned to him.
total interest comes to Rs. 350

we know from Simple interest formula,
S.I = p × r × t/100

Let number of year is T
so, S.I in Rs. 1000 + S.I in Rs. 1400 = 350

or, 1000 × 3 × T/100 + 1400 × 5 × T/100 = 350

or, 30T + 70T = 350

or, 100T = 350

or, T = 3.5 years or 3years and 6 months