GMAT Quantitative Reasoning Practice Test 1

Since we are trying to find the width of the deck, let $x=$ the width of the deck. Therefore, $x+x+20$ or $2x+20$ is the width of the entire figure. In the same way, $x+x+28$ or $2x+28$ is the length of the entire figure. The area of a rectangle is length $\times$ width, so use $A=l \times w$. Substitute into the equation: $884=(2x+20)(2x+28)$ Multiply using FOIL: $884=4x^2+56x+40x+560$ Combine like terms: $884=4x^2+96x+560$Subtract 884 from both sides: $884-884=4x^2+96x+560-884$$0=4x^2+96x-324$ Divide each term by 4: $0=x^2+24x-81$Factor the trinomial: $0=(x+27)(x-3)$ Set each factor equal to zero and solve: $x+27=0$ or $x-3=0x$ $=-27x=3$ Since we are solving for a length, the solution of -27 must be rejected. The width of the deck is 3 feet.