Answer:
x = 8 hours
Explanation:
add up all the parts,
the teachers spends 24 hours in a day to do 18 parts
there are 2 parts for grading per day, we need to solve for 3 days so 3*(parts) or 6 parts for grading
use ratio to solve for x,
24 hrs x (hours)
______ = __________
18 parts 3*(2 parts)
solve for x = (24 * 6 )/ 18 = 8 hours