1. 1/9
2. 0
3. -9
4. -1
Reasoning: To get the opposite of a number just add a negative sign or take it away. This can be done to all numbers other than 0
Answer: 20 mph
Explanation:
Speed is a physical quantity which is equal to the ratio between the distance covered (d) and the time taken (t):

In the first part of the problem, the plane flew a distance of d=400 mi in a time of t=2.5 h. The speed of the plane in this case was the difference between the proper speed of the plane, v, and the speed of the wind, w, since the plane flew opposite to the wind. So we can write:
(1)
During the return trip, the plane flew with a speed (v+w), since the wind was on the tail, and it took 2 hours to cover the same distance:
(2)
So we have two equations with two unknown variables. From (1), we get

Substituting into eq.(2)

So, the speed of the wind was 20 mph.
Answer:
50 combos
Step-by-step explanation:
Put it into an equation first in order to find x.
2x + 250 = 7x
Subtract 2x from both sides.
250 = 5x
Then divide both sides by 5.
x = 50
Therefore you need 50 combo meals in order to make the amount made equal to the amount paid.
<u>You can check your work by plugging in the number to both.</u>
$250 plus the $2 times 50 combo meals.
250 + 2(50) = 350
$7 times 50 combo meals
7 x 300 = 350
Answer:
706.5 ft^2
Step-by-step explanation:
area = radius^2 (Pi)
15^2(3.14) = 706.5