Find the area of the regular polygon. Round to the nearest tenth if necessary. 7.5 5.1

Question 1 solution:
You have two unknowns here:

Let the Water current speed = W

Let Rita's average speed = R

We are given two situations, where we can form two equations, and therefore solve for the two unknowns, W, R:

Part 1) W→ , R←(against current, upstream)
If Rita is paddling at 2mi/hr against the current, this means that the current is trying to slow her down. If you look at the direction of the water, it is "opposing" Rita, it is "opposite", therefore, our equation must have a negative sign for water:

R–W=2 - equation 1

Part 2) W→ , R→(with current)
Therefore, R+W=3 - equation 2

From equation 1, W=R-2,
Substitute into equation 2.
R+(R–2)=3
2R=5
R=5/2mi/hr

So when W=0 (still), R=5/2mi/hr

Finding the water speed using the same rearranging and substituting process:

1... R=2+W
2... (2+W)+W=3
2W=1
W=1/2mi/hr

7 0

2 years ago

A recipe says to use 3cups of flour to make 48 cookies. What is a constant of proportionality that related the number of cookies

MA_775_DIABLO [31]

Answer:

y=16 x=1

Step-by-step explanation:

For this one, we need to find the unit rate, which means how many cookies we can make using 1 cup of flour. To do that, we need to divide both the flour and the cookies by 3 to get 3/3=1 and 48/3=16. So the total amount of cookies made with one cup of flour is 16. So the constant proportionality is 16,1.

6 0

3 years ago

Jake can cut and split a cord of firewood in 9 fewer hours than Dwight can. When they work together, it takes them 6 hours. How

Luba_88 [7]

Answer:

18 hours for Dwight, 9 hours for Jake

Step-by-step explanation:

If J is the time it takes for Jake working alone, and D is the time it takes for Dwight working alone, then:

J = D − 9

Working together, Jake's speed plus Dwight's speed equals 1 cord per 6 hours.

1 / J + 1 / D = 1 / 6

Solve the system of equations by substituting for J:

1 / (D − 9) + 1 / D = 1 / 6

Multiply both sides by D − 9.

1 + (D − 9) / D = (D − 9) / 6

Multiply both sides by D:

D + D − 9 = D (D − 9) / 6

Simplify and solve:

2D − 9 = (D² − 9D) / 6

12D − 54 = D² − 9D

0 = D² − 21D + 54

0 = (D − 3) (D − 18)

D = 3 or 18

Since J = D − 9, D must be greater than 9. So D = 18 and J = 9.

That means it takes Dwight 18 hours working alone, and it takes Jake 9 hours working alone.

3 0

3 years ago