1. Martha pays 20 dollars for materials to make earrings. She makes 10 earrings and sells 7 for 5 dollars and 3 for 2 dollars. Write a numerical expression to represent this situation and then
find Martha's profit?

Numerical expression to represent this situation : 41 = 20 + P

Martha's profit is $21

Step-by-step explanation:

Total cost price for earrings for Martha = total money invested in material  to make earrings = $20

No. of ear rings made = 10

No. of earrings sold for $5= 7

Total Price for these 7 earrings= $5*7 = $35

No. of earrings sold for $2= 3

Total Price for these 3 earrings= $2*3 = $6

Total price for all of the ten earrings = $35+$6 = $41

We know that

selling price = cost price + profit

Total price for all of the ten earrings = Total cost price for 10 earrings + total profit made on those 10 earrings

let total profit be P

41 = 20 + P

Thus,

P = 41-20 = 21

numerical expression to represent this situation : 41 = 20 + P

Thus, Martha's profit is $21

The exterior angles of a polygon add up to 360º in measure. For a regular heptagon, each exterior angle has an equal measure xº, so that 7xº = 360º, or xº ≈ 51.43º. Interior angles supplement exterior angles, so they each have measure 180º - xº ≈ 128.57º. Multiply this by 7 to get a total of 900º.