Question

Danielle and Tracy are building a rectangular sandbox. Danielle has two boards that are equal in length, and Tracy has two boards that are each 5 feet longer than Danielle’s. They use the four boards as the four sides of their sandbox. Use the variable x to write an algebraic expression to relate the perimeter of the sandbox to the length of one of Danielle’s boards.

Answer 1

`P=4x+10`

Explanation:

Let

x -----> the length of Danielle's board in feet

y ----> the length of Tracy's board in feet

we know that

`y=x+5` ----> equation A

The perimeter of the sandbox is equal to

`P=2(x+y)` ----> equation B

substitute equation A in equation B

`P=2(x+x+5)`

`P=2(2x+5)`

`P=4x+10`