Sam deposited $350 into a savings account that paid 5% in simple interest. when he withdrew his money 8 months later, how much interest did he receive?

The equation for simple interest is
I = P x R% x T
I is simple interest
P is principal, which is the amount u deposit in
R% is the rate
And T means the time

However, this question didn't list whether 5% is per annual or per monthly.

Suppose it's oer annual,
From the numbers, we can substitute in
Interest = 350 x (5%/12) x 8
Note that since the amount of time is in months, and one year has 12 months, so we need to change the rate into per monthly.
Interest = 350 x (5%/12) x 8
Answer = $11.66666676

But suppose it's per monthly.
This time we don't need to divide the rate by 12.
Interest= 350 x 5% x 8
=$140