Question

A sum of money amounts to Rs. 20,800 in 5 years
and Rs. 22,720 in 7 years. Find the principal and
the rate of simple interest?

Answer 1

Answer:

We can get SI of 3 years = 12005 - 9800 = 2205

SI for 5 years = (2205/3)*5 = 3675 [so that we can get principal amount after deducting SI]

Principal = 12005 - 3675 = 6125

So Rate = (100*3675)/(6125*5) = 12%

Answer 2

Answer:

principal-16000, rate of simple interest-6%

Explanation:

sum of money in 5 yrs=20,800

and in 7 yrs=22,720

so in two yrs =22,700-20,800

=1920

in 1 yrs=1920÷2=960

in 5 yrs=960×5=4800

so Principal amount =20,800-4800

=16000

rate of interest =4800×100/5×16000

=6%