Translate to a system of equations and solve.

Question

Darrin is hanging 400 feet of Christmas garland on the three sides of fencing that enclose his rectangular front yard. The length is fifteen feet less than three times the width. Find the length and width of the fencing (in feet).

Answer 1

l = 3w - 15

l + 2w = 400

 

We can solve two different ways...

 

3w - 15 + 2w = 400

 

Solve for w, then plug your answer into the first equation to find l.

 

Orrr, solve the 2nd equation for l...

 

l = 400 - 2w

 

Since l also equals 3w - 15, they equal each other.

 

400 - 2w = 3w - 15

 

Again, solve for w and plug your answer into the first equation to find l.