Mr Roberts had 9512 in savings. He saved another 488.00 He then used all his money to buy 500 books. He sold the books for $35.00 each. How much dis Mr. Roberts earn from selling each book

9512 + 488 all divided by 500 = 20.  He spent 20 dollars per book.

If he sold each book for 35, and each book cost him 20, then he made $15 on each book.

Okay.

So he had $9512 and saved another $488 so,

9512 + 488 = 10000

He used that to buy 500 books so,

10,000 / 500 = $20 per book

He then sold the books for $35 each. If he paid $20 per book then $35 - $20 = $15

Mr. Roberts earned $15 per book by sellin

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: the first one

step-by-step explanation: use a calculator and divide the minutes by the dollars.