I will assume you are using compound interest.
<span>let the amount invested be x </span>
<span>x(1.0575)^25 = 85000 </span>
<span>x = 85000/1.0575^25 = $21,009.20</span>
Step One
Find the fraction left.
Starting amount = 7/8 pound
Used amount = 1/7 of a pound.
The common denominator of these two fractions is 8 * 7 = 56
Amount left = amount started with - amount used
Amount left = 7/8 - 1/7
Amount left =

Amount left =

Amount left = 41 / 56 pounds
Step Two
Convert the Answer to ounces.
Ounces = (41/56) * 16
Ounces = 11.71 ounces almost 11 3/4