Suppose that Jane borrows 7800 dollars from a bank on April 24 at an annual rate of 7 percent simple interest. How much does she owe on August 14 of the same year?

Pt = Po + Po*r*t,

r = APR.
t = 3.3333mo/12mo = 0.27777 yrs.

Pt = 7800 + 7800*0.07*0.27777 = $7951.67