Final answer:
The equation to solve for the length of Kevin's garden, given a width of 30 feet and a perimeter of 140 feet, is 140 = 2l + 60. After simplifying, we find that the length is 40 feet. The correct answer is D. 2x + 30 - 140.
Step-by-step explanation:
The question revolves around the formula for the perimeter of a rectangle, which is P = 2l + 2w, where P is the perimeter, l is the length and w is the width. Given that Kevin needs a fence with a total perimeter of 140 feet and the width is 30 feet, we can set up the equation to solve for the length.
By substituting the known values into the perimeter formula, we get 140 = 2l + 2(30). Simplifying this equation, we have 140 = 2l + 60. To solve for l, we subtract 60 from both sides giving us 80 = 2l and then divide both sides by 2, resulting in 40 = l. Therefore, Kevin's garden length is 40 feet.
The perimeter of a rectangle is found by adding the lengths of all four sides. In this case, we are given that the width of the garden is 30 feet. Let's represent the length of the garden as x.
So, the equation for the perimeter is: 2(width) + 2(length) = perimeter. Substituting the given values, the equation becomes: 2(30) + 2(x) = 140. Simplifying this equation will give us the equation that can be used to solve for the length of the garden.