Selma wants to know if seventh grade students prefer to do their math homework in silence or with background music. She polled
the 30 students in her music class. Ten students preferred to do their math homework in silence, and twenty students preferred to do
their math homework with background music.
Is there a sampling bias in the situation above?
A.
Yes. Students in the music class will probably enjoy listening to music more than other students.
B.
There is not enough information.
C. Yes. Selma is only curious about 7th grade students, but 6th grade students may prefer background music too.
D. No. Selma picked a completely random sample for her study.

there are lots of ways.   pick's theorem tells us if the vertices are lattice points the area a is

a = b/2 + i - 1

where b is the number of boundary lattice points and i is the number of interior lattice points.

in the figure i count b=16, i=50 so

a = 8 + 50 - 1 = 57

let's try the shoelace formula.   the area is half the sum of the cross products of the sides.  

a(-2,6)   -2(2)-6(-5) = 26

b(-5,2)   -5(-3) - 2(-2) = 19

c(-2,-3) -2(-3) - (-3)(4) = 18

d(4,-3)   4(3) - (-3)(5) = 27

e(5,3)   5(3) - 3(1) = 12

f(1,3)     1(6) - 3(-2) = 12

a(-2,6)

each of the cross products is twice the area of the triangle with the associated side and one vertex the origin. so the area of abo=26/2=13.

area = (1/2) (26 + 19 +   18 + 27 + 12 + 12) = 57

that checks!

answer is:

1.75 pounds

41*67/2=1373.5

step-by-step explanation:

i just used a calculator