AAPL wrote:Magoosh

Bill took 4 math tests, and each test received a score out of 100. What was Bill's average (arithmetic mean) score for all 4 tests?

1. Bill's first 3 tests received an average score of 50.
2. Bill's last 2 tests received an average score of 50.

OA E

Target question: What was Bill's average (arithmetic mean) score for all 4 tests?

Statement 1: Bill's first 3 tests received an average score of 50.
Since we don't have any information about the 4th test, statement 1 is NOT SUFFICIENT

Statement 2: Bill's last 2 tests received an average score of 50.
Since we don't have any information about the first two tests, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
There are several scnenarios that satisfy BOTH statements. Here are two:
Case a: The 4 test scores, in order, are {50, 50, 50, 50}. In this case, the answer to the target question is The average score for all 4 tests is 50
Case b: The 4 test scores, in order, are {0, 50, 100, 0}. In this case, the answer to the target question is The average score for all 4 tests is 150/4
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer: E

Cheers,
Brent