Answer:20,5369%
Explanation:We know APR is the Annual Percentage Rate that is paid over a loan. If we are to pay during 78 months at most $510 each month, then we could pay in total 510*78=$39780 in the course of the six years and a half that constitute the 78 months. This means that yearly we can pay in interest $39780/6,5=$6120 each year, this represents the interest over the loaned money, i.e., the $29800. Then the APR is
[tex]\\\frac{6120}{29800} =20,5369\%[/tex] annualy or 1,71141% monthly and it is the highest APR you could afford, 20.5369%