Sales Team A at Drive-A-Lot Cars sells nine (9) cars during the first week of the new sales period. Over the next three weeks, they sell six (6) cars, ten (10) cars and seven (7) cars. What is the team’s average weekly sales for the four weeks?

47 - 90 = 43

43 - 180 = x

x = 137

look at the picture.

1.

ef : ab = 2 : 3

gf : cb = 2 : 3

gh : cd = 2 : 3

he : da = 2 : 3

2.

∠a ≅ ∠e

∠b ≅ ∠f

∠c ≅ ∠g

∠d ≅ ∠h

3.

use pythagorean theorem:

the length of the abcd trapezoid sides:

|ab| = 3 cm

|bc| = 10 cm

|cd| = 3(3) cm = 9 cm

|da| = 8 cm

the perimeter of abcd = 3 + 10 + 9 + 8 = 30 cm

the ratio of perimeters of the tarapezoids is equal 2 : 3.

substitute:

      cross multiply

      divide both sides by 3