Because if you plug those numbers into the graph, only C and D fit. Now we have to look at the unit price. If LaMar buys 2 lbs and pays 3.00 dollars, we know that the unit price is 3/2=1.5 dollars per pound. You could also check with the other peoples. $7.5/5lbs=1.5 dollars. $4.5/3lbs=$1.5
It would be 20 hrs because if you put them both in an equation aka y=25x+100 and y=30x just plug in numbers into the x until they both have the answer which in this case is 20
