Respuesta :

Answer:

The rate of interest is 8.33%  per annum.

Step-by-step explanation:

To find the rate of interest simple use the formula for simple interest that is:

(P × R × T)/ 100 = I

where:

P = initial amount : 840

R = rate of interest per time period : to find

T = time in years : 3

I = interest : 210

Now rearrange the formula:

I/(P x T) x 100 = R

( 210 x 100)/(840 x 3) = R

21000/2520 = R

8.33 % = R

Answer:

Step-by-step explanation:

Use simple interest formula,

Simple Interest = (Principal × Rate × Time)/100

           Rate       = (simple interest × 100)/(principal × time)

                          = (100 × 210)/(840 × 3)

Calculate

                          ≈ 8.33..%

                          ≈ 8.3% to the nearest tenth