PS from PR

[rabab]

The output of a factory was raised by 10% to keep up with rising demand. To handle the holiday rush, this new output was increased by 20%. By approximately what percent would the output now have to be decreased in order to restore the original output?

a. 20%
b. 24%
c. 30%
d. 32%
e. 79%

IOM 32%.

[toudavis]

Agreed.

Start with 100(1.10) = 110
110(1.20) = 132

(Orig - New)/New = (100-132)/100 = 32/100 or 32%

[rabab]

But PR says the answer should be 24%. I don't get it.

[mental]

IMO B

rabab and toudavis

going with ur values
Start with 100(1.10) = 110
110(1.20) = 132

current level is 132, old level 100

to bring 132 to 100 we have to reduce by 32

so 32 is how much percent of 132:
32/132 is approx 24%

[rabab]

IMO B

rabab and toudavis

going with ur values
Start with 100(1.10) = 110
110(1.20) = 132

current level is 132, old level 100

to bring 132 to 100 we have to reduce by 32

so 32 is how much percent of 132:
32/132 is approx 24%

I see. Thanks for the help!

[VP_Jim]

Nothing to add here really - the explanation above (from mental) is fine. Start with 100 and then figure it out from there.

I did want to say, though, that this is a classic GMAT trap: tricking people into saying that the percent decrease from x to y would be the same as the percent increase from y to x (in this case, the percent decrease from 132 to 100 is not the same as the percent incresae from 100 to 132).

Be careful!

[vishubn]

Thanks mental for the explanation and Rahab for posting the question !
tricky one


Vishu

[raunekk]

imo:B