Question 1124867
Let the principal be x.
Then the amount is 3x.
Let the rate be r.
Time=t=15 years
In simple interest amount=P*t*r/100
Plugging in the values we get,
3x=x*15*r/100
Multiplying both sides of the equation by 100 we get,
3x*100=15rx
300x=15rx
15r=300
r=20
The rate of interest is 20%.