A rectangular garden has a perimeter of 40 m. If the length is increased by 2 m and the width decreased by 2 m, the area becomes 96 m². What were the original dimensions?

Jawaban: 12 m by 8 m

Let original length L and width W. 2(L+W)=40 ⇒ L+W=20. New dimensions: L+2 and W-2. Area: (L+2)(W-2)=96. Substitute W=20-L: (L+2)(18-L)=96 ⇒ -L²+16L+36=96 ⇒ L²-16L+60=0 ⇒ (L-10)(L-6)=0 ⇒ L=10 or 6. Since L>W, L=12? Wait, if L=10, W=10, then new area (12)(8)=96, so original 10x10 works. But 12x8 also gives L+W=20 and new area (14)(6)=84, not 96. So original must be 10x10. The option 10 m by 10 m is correct. So answerIndex 3. I need to fix this.