area = ( top rule + bottom rule ) × height / 2
area = ( 2 + 3 ) × 4 / 2
area = 5 × 4 / 2
area = 20 / 2
area = 10
It's b because you have to round up
I can't see the pages to be able to help you sorry
y=4x+40
x represents the number of minutes
y is the total
40 because he already graded 40 papers, and 4x because that's how many phred grades times the number of minutes