Question

A borrows RS8000 at 12% per annum simple intrest and B borrows RS 9100 at 10% per annum simple intrest.In how many years will their amount be equal

Answer 1

 yes the exact amount will be  equal after 22 years. but i have written approximately near value that is 18 years.

Answer 2

Let the amount of A and B be equal after t years.
Now simple interest for A after t years = 800012t100960t
Then, the total amount of A = 8000 + 960t......(i)

Similarly the simple interest for B after t years = 910010t100910t
Then, the total amount of B = 9100 + 910t.....(ii)

Now, equating (i) and (ii) we have;
8000960t9100910t
960t910t91008000
50t1100
t11005022
So the amount of A and B will be equal after 22 years.