Question

in what time will the simple interest on a certain sum of money at 10% per annum be 2/5 of itself​

Answer 1

Answer:

The time period is 4 years

Step-by-step explanation:

P = principal (initial amount)

R = rate of interest per cent per year = 10

T = number of years = ?

We know that

Simple interest (SI) = P*R*T/100

We are given that SI is 2/5*P

Therefore:

2/5*P = (P*10*T)/100

2/5 = (10*T)/100

2*100 = 5*10*T

200 = 50*T

T = 4

The required time period is 4 years

Verification

At 10% interest, simple interest earned on "P" for a period of four years will be:

SI = (P*10*4)/100

SI = 40/100*P

SI = 2/5*P

The simple interest is 2/5 times the principal