Question

Edwin and Anthony are building a rectangular deck in their backyard.The Longer side is 2 more than 1/3 the perimeter. The shorter side is 1/10 of the perimeter. Know that the longer side is 9 ft longer than the shorter side. What is the Perimeter of the deck?

Answer 1

Answer: The perimeter is 30ft.

Explanation:

Let's define:

L = length of the longer side.

S = length of the shorter side.

P = perimeter

we know that for a common rectangle:

P = 2*S + 2*L

We aso know that:

L = 2ft + (1/3)*P

S = (1/10)*P

L = S + 9ft.

So we have a system, let's find the perimeter only using this system (So i will ignore the equation for the perimeter of a rectangle)

First, we can replace the third equation in the first equation, now we have a system with only two equations:

S + 9ft = 2ft + (1/3)*P

S = P/10

Now we can replace the second equation in the first equation, and get:

P/10 + 9ft = 2ft + P/3

Now let's solve this for P.

9ft - 2 ft = P/3 - P/10

7ft = P( 1/3 - 1/10) = P*( 10/30 - 3/30) = P*(7/30)

(30/7)*7ft = P = 30ft.

The perimeter is 30ft.