800score.comhttp://www.800score.com/forum/ GRE Statistics (Select One)http://www.800score.com/forum/viewtopic.php?f=12&t=3526 Page 1 of 1

Author:  questioner [ Mon Dec 06, 2010 2:00 pm ]
Post subject:  GRE Statistics (Select One)

Three students were given three tests, the results of the first two tests are shown above. Student 1 and Student 3 received equal scores on Test 3. As a result, Student 1’s average (arithmetic mean) score over the three tests was 50 percent higher than Student 3’s average. What was the score Students 1 and 3 received on Test 3?

A. 33
B. 34
C. 35
D. 36
E. 39

(B) Let x be the score that both Student 1 and Student 3 received on Test 3.
Since Student 1's average is 50% higher than Student 3's average, Student 1's average is 1.5 times that of Student 3.
The average for Student 1 is (30 + 50 + x)/3, and the average for Student 3 is (14 + 28 + x)/3.

So we can solve for x as follows:
(30 + 50 + x)/3 = ((14 + 28 + x)/3) × 1.5
(80 + x)/3 = ((42 + x)/3) × 1.5
(80 + x)/3 = (63 + 1.5x)/3
80 + x = 63 + 1.5x
17 = 0.5x
x = 34.

The correct answer is choice (B).
----------

Can you tell me how you got 1.5 for 50%? I would think 50 percent is .5.

Thank you.