jwin125 wrote:

When a class of n students is divided into groups of 6 students each, 2 students are left without a group. When the class is divided into groups of 8 students each, 4 students are left without a group. What is the smallest number of students that can be added to or removed from the class so that the resulting number of students can be equally divided into groups of 12 students each?

Please follow the rules and so not miss out on giving choices..

Our requirement is that the final number has to be MULTIPLE of 3 and 4

Given..

\(n=6x+2\)... so n is a multiple of 2 but not of 3... Example 2,8,14,20,26,32,38,44,50

\(n=8y+4\)... n is surely a multiple of 4.. example 4,12,20,28,36,44,52

So numbers are \(20+24a...\)

Also we can get this from (FIRSTCommon Number+LCM of 6,8)When you divide (20+24a) by 12, 24a is div by 12 and 20 gives a remainder of 8..

So we can add 4 or remove 8 to get n div by 12..Least is 4..

Ans is 4

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1) Absolute modulus : http://gmatclub.com/forum/absolute-modulus-a-better-understanding-210849.html#p1622372

2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html

3) effects of arithmetic operations : https://gmatclub.com/forum/effects-of-arithmetic-operations-on-fractions-269413.html

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