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23 Jul 2018, 03:17
Kudos
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E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
25%
(medium)
Question Stats:
74% (01:31) correct
26%
(01:21)
wrong
based on 333
sessions
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Not Attempted Yet
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.
(1) Bill's first 3 tests received an average score of 50.
(2) Bill's last 2 tests received an average score of 50.
23 Jul 2018, 07:36
Kudos
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Each statement by itself is obviously insufficient:
(1) we are definitely unable to find the fourth grade
(2) we are definitely unable to find the first two grades
Combined: Let's pick up a couple of scenarios.
Scenario #1: He got 100, 50 and 0 to meet statement (1). To meet statement (2), he'd have gotten 0 and 100 on the third and fourth tests, which means he got 100, 50, 0 and 100 in his tests. The average would be 250/4.
Scenario #2: He got 50, 50 and 50 to meet statement (1). To meet statement (2), he'd have gotten 50 and 50 on the third and fourth tests, which means he got 50 an all 4 tests. The average would be 200/4 = 50.
Scenarios are inconsistent so there's not enough information to answer the question.
Answer E.
(1) we are definitely unable to find the fourth grade
(2) we are definitely unable to find the first two grades
Combined: Let's pick up a couple of scenarios.
Scenario #1: He got 100, 50 and 0 to meet statement (1). To meet statement (2), he'd have gotten 0 and 100 on the third and fourth tests, which means he got 100, 50, 0 and 100 in his tests. The average would be 250/4.
Scenario #2: He got 50, 50 and 50 to meet statement (1). To meet statement (2), he'd have gotten 50 and 50 on the third and fourth tests, which means he got 50 an all 4 tests. The average would be 200/4 = 50.
Scenarios are inconsistent so there's not enough information to answer the question.
Answer E.
23 Jul 2018, 21:06
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Bunuel
Let the tests be a,b,c,d
Statement 1:
(a+b+c)/3 = 50
a+b+c = 150 --- (1)
Insufficient
Statement 2:
(c+d)/2 = 50
c+d = 100 --- (2)
Insufficient
1&2:
Even if we combine both statements we still can't get the whole sum. Hence Insufficient
Answer E
