Please check my math answer

[thatguy47]

A tree of height y meters has, on average, B branches, where B = y - 5. Each branch has, on average, n leaves where n = 7B2 - B. Find the average number of leaves of a tree as a function of height.

Average number of leaves of a tree =

Would it be:

7y - 71 + 180/y

 

[wjm11]

A tree of height y meters has, on average, B branches, where B = y - 5. Each branch has, on average, n leaves where n = 7B2 - B. Find the average number of leaves of a tree as a function of height.

Is "7B2" possibly supposed to mean "7 times B squared"? If so, your answer is not correct. Please show all the steps that led up to your answer. Note: you can show "B squared" as b^2.

 

[thatguy47]

Yeah, its 7B^2

Here's my work:
n= 7[y-5]^2 - [y-5]
= 7[y^2 - 10y + 25] - y +5
= 7y^2 - 71y + 180

To find the avg I divided n by y to get:
7y - 71 + 180/y

 

[thatguy47]

Is that right?

 

[wjm11]

A tree of height y meters has, on average, B branches, where B = y - 5. Each branch has, on average, n leaves where n = 7B^2 - B. Find the average number of leaves of a tree as a function of height.

Average number of leaves of a tree =
n= 7[y-5]^2 - [y-5]
= 7[y^2 - 10y + 25] - y +5
= 7y^2 - 71y + 180

n = 7y^2 - 71y + 180 is correct; stop here. No need to divide by y since the given equations are already for “averages”.