Question

A certain sum amounts to *798.60 after 3 years and 878.46 after 4 years. Find the
interest rate and the sum.​

Answer 1

Answer:

Hope it helps you ..thanks

Answer 2

Answer:

It is given that 

Amount after 3 years  = 798.60 

Amount after 4 years = 878.46

So the difference = 878.46 - 798.60 = 79.86

Here 79.86 is the interest of 798.60 for 1 year.

We know that 

Rate = (SI×100)/(P×t)

Substituting the values 

=(79.86×100)/(798.60×1)

Multiply and divide by 100 

=(7986×100×100)/(79860×100×1)

=10%

Here 

A= P(1+r/100)n

It can be written as

P=A÷(1+r/100)n

Substituting the values 

P= 798.60÷(1+10/100)3

By further calculation 

P=79860/100×10/11×10/11×10/11

P=600