A garden's length is 5 more than 3 times its width. If the perimeter is 58 feet, what is the area of the garden?

From the perimeter condition, let the width be $w$ and the length $3w+5$. Then $2(w+3w+5)=58$ gives $w=6$ and the length is $23$. The area is $6\cdot23=138$ square feet, choice J. Check the perimeter: $2(6+23)=58$. Choice F ($96$) multiplies $6$ by $16$, a wrong length. Choice H ($144$) is $12^2$, a wrong shape. Choice G ($196$) is $14^2$, which would be a square with perimeter $56$ rather than $58$. Area is length times width, so make sure you solve for both dimensions before multiplying.