Find the interest due on $700 at 10.5% for 90 days ... 19.11. 18.38

To answer the question, I assume that the given interest is annual and simple interest. The interest acquired by the investment in simple interest is given by the equation,

I = P x i x n

where I is interest, P is present worth, i is rate and n is number of interest period. Assuming that a year is 360 days,

I = ($700) x (0.105) x (90/360)

The answer is 18.375. Therefore, the interest due is approximately equal to $18.38.