Question

the simple interest on a sum of money for 5 years at 7% p.a is Rs 800 more than the simple interest on the same sum for 3 years at 9% per annum. find the original sum of money​

Answer 1

Answer:

10000rs.

Step-by-step explanation:

let the principal = rs. P

time= 5 years

rate = 7% per annum

original simple interest = P×R×T/100

=P×7×5/100

=7P/20

therefore original simple interest = rs.7P/20

now, principal = rs. P

time=3 years

rate= 9% per annum

new simple interest= P×R×T/100

= P×9×3/100

= 27P/100

therefore new simple interest = rs.27P/100

according to question:

original simple interest - New simple interest = 800

7P/20 - 27P/100= 800

35P - 27P/100 =800

8P/100=800

P=800×100/8

P= 10000