Find the interest due on $1,200 at 8% for 240 days.

Let us use 360 days for the 1-year term.

principal = 1,200
interest rate = 8% unless otherwise stated, this rate is per annum or annual rate.
term = 240 days

Simple Interest = Principal * interest rate * term
S.I = 1,200 * 8% * 240/360
S.I = 1,200 * 0.08 * 0.667
S.I = 64.032  rounded off to 64

The interest due 1200 at 8% rate is 64 in 240 days.