Answer:
2 13/40 feet or 2.325 ft
Step-by-step explanation:
The length of the plank = 8⅕ feet
To determine many feet should be cut off, subtract 5⅞ feet from 8⅕ feet.

Step 1: Convert both fractions to improper fractions.

Step 2: Find the lowest common multiple of the denominators 8 and 5.

2 13/40 feet of the plank should be cut off.