Are you sure your in high school, also it's answer #3.
We are trying to represent the change in position of a bird flying down 7 ft to the ground.
Often, for the y axis- up is positive and down is negative.
Change in position is displacement- how far it was from the starting point
( different from distance which is how far is traveled
ex. doubling back would have distance they traveled some distance while the displacement is 0 because they are back to where they started).
The bird is going down 7 ft from where it originally was, which can be represented by
Bird's displacement = -7 ft
B. 875
1/4 of 500 is 125. So 125 is how much they pay for day approx. 125 times the seven days will be 875.
Answer: 285.2 kg
Step-by-step explanation:
Given
The volume of helium in the balloon is 
The density of the helium is 
Mass of the helium gas is given by the product of density and volume

Thus, the mass of gas is 285.2 kg