Data Sufficiency

Does the following statement provide sufficient information to answer the question? Show how if it does.

Question: What was the percent increase in profits for Company X between 1991 and 1993?

Statement: The average of the annual profits of 1991 and 1993 was 12.5% higher than the profit in 1991.

SFtraveler wrote:Does the following statement provide sufficient information to answer the question? Show how if it does.

Question: What was the percent increase in profits for Company X between 1991 and 1993?

Statement: The average of the annual profits of 1991 and 1993 was 12.5% higher than the profit in 1991.

Q: (%1993 - %1991)/ %1991 ? Call %1991=X and %1993=Y --> (X-Y)/Y
st: (X+Y)/2 = X +0,125 (12.5%) --> (X+Y) = 2*X +0,25 --> Y = X +0,25; [X -(X+0,25)]/ X = 0,25/ X; suppose X=100% OR 1, then change --> 0,25/1=0,25 OR 25% Sufficient.

Night reader wrote:

SFtraveler wrote:Does the following statement provide sufficient information to answer the question? Show how if it does.

Question: What was the percent increase in profits for Company X between 1991 and 1993?

Statement: The average of the annual profits of 1991 and 1993 was 12.5% higher than the profit in 1991.

Q: (%1993 - %1991)/ %1991 ? Call %1991=X and %1993=Y --> (X-Y)/Y
st: (X+Y)/2 = X +0,125 (12.5%) --> (X+Y) = 2*X +0,25 --> Y = X +0,25; [X -(X+0,25)]/ X = 0,25/ X; suppose X=100% OR 1, then change --> 0,25/1=0,25 OR 25% Sufficient.

Nightreader, why would it be (X-Y)/Y?

SFtraveler wrote:Does the following statement provide sufficient information to answer the question? Show how if it does.

Question: What was the percent increase in profits for Company X between 1991 and 1993?

Statement: The average of the annual profits of 1991 and 1993 was 12.5% higher than the profit in 1991.

Let's rephrase...

If a is the profits for Company X in 1991 and b is the profits for Company X in 1993, such that a < b, then what is (b - a)/a × 100 = {(b/a) - 1} × 100? All we need to do is to find b/a only.

Statement adds...

½ (a + b) = 1.125 a

Or a + b = 2.25 a

Or b = 1.25 a

Or b/a = 1.25


Hence the given statement is sufficient to answer the stem.