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by cans » Mon May 30, 2011 3:28 am
The area company wants to add an area code composed of 2 letters to every phone no. In order to do so, the company chooses a special sign language containing 124 different signs. Company used only 122 of them and 2 were left unused. How many additional area codes can be created if company uses all 124 signs?
a)246
b)248
c)492
d)15,128
e)30,256
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by itsmebharat » Mon May 30, 2011 4:03 am
https://www.beatthegmat.com/an-area-code ... 83540.html
I am not an Expert, please feel free to suggest if there is an error.
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by amar66 » Mon May 30, 2011 4:09 am
The best answer is C.
The phone company already created 122*122 area codes, now it can create 124*124.
1242-1222=(124+122)(124-122) = 246*2 = 492 additional codes.
There are other ways to solve this question. However this way is usually the fastest.
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