Data Sufficiency

last year, the five employees of company x took an average of 16 vacation days each. What was teh average number of vacation days taken by teh same employees this year?

1. three employees had a 50% increase in their number of vacation days, and two employees had a 50% decrease/


2. Three employees had 10 more vacation days each and two employees had 5 fewer vacation days each.


qa is B

Obviously, statement 1 is insufficient because we need to know what the original number the increases and decreases are based on. BUT in statement 2, hwo is this sufficient. My specific question is WHERE do we know what to base the increase and decrease of days from. I ruled this out because we dont know what the original days the increases are based on. I ruled it out since we dont know if the 10 day increase is from an origiinal of 1 day each or an original of 20 days each. Can we make sense of this?

Enginpasa1 wrote:last year, the five employees of company x took an average of 16 vacation days each. What was teh average number of vacation days taken by teh same employees this year?

1. three employees had a 50% increase in their number of vacation days, and two employees had a 50% decrease/


2. Three employees had 10 more vacation days each and two employees had 5 fewer vacation days each.


qa is B

Obviously, statement 1 is insufficient because we need to know what the original number the increases and decreases are based on. BUT in statement 2, hwo is this sufficient. My specific question is WHERE do we know what to base the increase and decrease of days from. I ruled this out because we dont know what the original days the increases are based on. I ruled it out since we dont know if the 10 day increase is from an origiinal of 1 day each or an original of 20 days each. Can we make sense of this?

(2) tells us that the TOTAL number of vacation days this year is 20 more (3*10 - 2*5) than last year.

We know that last year the total # of vacation days was 16*5 = 80.

So, this year the total number is 80 + 20 = 100.

100 days spread out over 5 employees gives us an average of 20/employee: sufficient, choose (b).

There are other (and quicker) ways to make the same calculation, but since this is a DS question, we didn't really need to do the math anyway, as long as we recognize that if we can figure out the total # of vacation days and we know the # of employees, we can solve for the average.

A great first step in DS is to write down ANY formula that applies. Just jotting down avg = sum/# might have given you the insight you needed to see that (2) was suffiicient.

Yes, (2) was suffiicient

yeah, I bought the manhattan gmat tests as well. they're pretty long winded and overly complicated generally. the difficulty level isn't beyond reasonable, as much as the questions take far more time to do than real gmat questions do. I looked at this one and didn't really know what to do with it, but when I saw the solution, i felt pretty dumb for not getting it.

resilient wrote:last year, the five employees of company x took an average of 16 vacation days each. What was teh average number of vacation days taken by teh same employees this year?

1. three employees had a 50% increase in their number of vacation days, and two employees had a 50% decrease/


2. Three employees had 10 more vacation days each and two employees had 5 fewer vacation days each.


qa is B

Obviously, statement 1 is insufficient because we need to know what the original number the increases and decreases are based on. BUT in statement 2, hwo is this sufficient. My specific question is WHERE do we know what to base the increase and decrease of days from. I ruled this out because we dont know what the original days the increases are based on. I ruled it out since we dont know if the 10 day increase is from an origiinal of 1 day each or an original of 20 days each. Can we make sense of this?

stmt 2 can give the new avg. because the total sum of vacation is increased by 20 and people remains same =5
hence B