For the first question, we have to use the formula of simple interest, which is
[tex] Interest= Principal * rate * time [/tex]
Substituting the values
[tex] Interest = 250*0.027*1=6.75 [/tex]
Second question
[tex] Amount = principal + Principal * rate * time
\\
Amount = 389.42+389.42*0.032*7 =$476.65
[/tex]
Third question
[tex] Amount = principal + principal* rate * time
\\
Amount = 1567.12+1567.12*0.019*(9/12) = $1589.45 [/tex]