Help me and please explain it thoroughly to me

29

Step-by-step explanation:

P = 2*length + 2*width

P = 115

length = 28.5

width = ?

2*28.5 + 2*width = 115

2* width = 115 - (2*28.5)

2* width = 115 - 57

2* width = 58

width = 58 / 2 = 29

(checking by plugging in 29 as width and 28.5 as length into the formula)

people grow faster than other people.

step-by-step explanation:

should you really be posting this isn't math boi.

let x and 400 - x be the two numbers.  

==> 0.80x + 0.85(400 - x) = 400 - 68 from the statement of the problem.  

< ==> 0.80x + 0.85(400 - x) = 400 - 68  

==> 340 - 0.05x = 332  

< ==> -0.05x = -8 ==> x = 160, the first number ==> 400 - x = 240, the second number.