A worker can assemble 3 shelf units each hr. During the 5th hr...so the shift has been going on for 5 hrs...at 3 units per hr = (3 * 5) = 15 units assembled during the shift....and if there was 115 units in the warehouse, then that means before the shift, there were (115 - 15) = 100 units assembled <=
The fourth vertex would be at point (-9,1).
The slope from (5,-4) to (3,4) is -8/2 or -4.
So I did that with (-7,-7) to the fourth vertex to get the answer.
It should be 4 qt + 1 qt is 1 gallon, I think
4.2% of 50 is 2.1
So 2.1 is your answer