Question

How much should you invest at 4% simple interest in order to earn $50 interest in 6 months

Answer 1

Simple interest formula
Interest = Pit = $50
P=principal (initial investment)
i=annual interest rate = 0.04
t=time in years = 6 months = 0.5 years

Substitute values,
$50 = P*0.04*0.5 
Solve for P
P=$50/(0.04*0.5)=$2500