If the length of a rectangle is increased by 20 percent and the width

Plunkster82 , there are threads here (and info elsewhere) that answer your question.

My two cents':

1) check your answers. On this kind of question, try different numbers. The square as rectangle is a great idea. But with percentages, try to use values such as 10 and 100 that give you a base of 100. Try 10 here as original L and W. You'll get 96 vs 100: Four percent smaller.

2) write down all but the most simple things, neatly. One of my favorite experts at gmatclub is a fan of mental math. I am not.

3) Check out these threads:

Tip of the Week, posts from Brian Galvin at Veritas Prep and great links from Bunuel: HERE

Another, HERE

Another, HERE

After those, I would run two Google searches with these terms:
1) GMAT dumb silly mistakes gmatclub; and
2) same, but omit "gmatclub"

Hope it helps.

We can let L = the original length and W = the original width; thus, the original area of the rectangle is LW and the new area is 1.2L x 0.8W = 0.96LW, so the area is decreased by 4%.

Answer: B

New area how come 1.2l?

Sent from my MI 5 using GMAT Club Forum mobile app

Hey Akshusaya ,

1.2 L is the the new length when the original length was increased by 20%.

New area = (1.2 L) * (0.8W) = 0.96LW

Does that make sense?

\(20 - 20 +\frac{(20*-20)}{100}\)

= \(-4\)

There will be a net decrease of 4% , answer must be (B)

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