The most simple form (I'm defining the parabola to be an upwards-opening one) would be
Each time a rider is added, the cost of lunch goes up $4.25. L=n4.25
To find the cost per pound you simply divide the amount paid by the amount purchased
For Beef it would be:
$7.20 ÷ 2.0 = $3.60
For Pork it would be:
$8.10 ÷ 2.5 = $3.40
For Chicken it would be:
$9.80 ÷ 3.5 = $2.8
What is a hundred? A hundred would be 846. What does it mean to round to the nearest hundred pounds? It's to make the number end with 00, so 100, 200, 300. If you have 467, you'd round it to 500, because that's the closest hundred it can be rounded to. So the answer would 25,800.