i need the answers to all these questions asap my sister is waiting for me to have the answers and i really don't want to tell her i don't know so please give me the answers please

Question

ian borrows $3580 at 31% simple interest per year. When Ian pays the loan back 7 years later, how much interest does Ian pay?

Zach borrows $1910 at 2.6% simple interest per month. When Zach pays the loan back 3 years later, how much interest does Zach pay?

Craig borrows $1000 at 9% simple interest per year. When Craig pays the loan back 11 years later, what is the total amount that Craig ends up repaying?

Larry borrows $1300 at 5% simple interest per month. When
Larry pays the loan back 3 years later, what is the total amount that Larry ends up repaying?

Fred borrows $40 at 0.8% simple interest per month. When Fred pays the loan back 2 years later, how much interest does

Answer 1

I = P*R*T

all questions use that formula, I will do one of them you do the others.
- important to note that whatever units you are using for T, the R must be the rate for that time period.

Zach borrows $1910 at 2.6% simple interest per month. When Zach pays the loan back 3 years later, how much interest does Zach pay?
I = ?
P = 1910
R = .026
T = 36 , number of months in 3 years
I = 1910(.026)(36) = 1787.76 , (high because of the nasty interest rate)