oquiella wrote:5. Five people - Adam, Bob, Craig, Daniel and Evan - are of different ages. Daniel is
younger than both Adam and Craig. Craig is younger than Bob but older than Evan.
Who among the five is the oldest?
(1) The average age of Adam and Bob is less than the average age of Craig and
Evan.
(2) The average age of Bob and Craig is less than the average age of Adam and
Evan.
From the prompt:
D < A and D < C.
E < C < B.
Statement 1: The average age of Adam and Bob is less than the average age of Craig and Evan.
(A+B)/2 < (C+E)/2
A+B < C+E.
Adding together A+B < C+E and C < B, we get:
(A+B) + C < (C+E) + B
A < E.
Linking together D < A, A < E and E < C < B, we get:
D < A < E < C < B.
B is the oldest.
SUFFICIENT.
Statement 2: The average age of Bob and Craig is less than the average age of Adam and Evan.
(B+C)/2 < (A+E)/2
B+C < A+E.
Adding together B+C < A+E and E < C, we get:
(B+C) + E < (A+E) + C
B < A.
Linking together E < C < B and B < A, we get:
E < C < B < A.
Since D < A, A is the oldest.
SUFFICIENT.
Whereas B is the oldest in statement 1, A is the oldest in statement 2.
This problem is FLAWED.
On the GMAT, the two statements CANNOT contradict each other.
I would ignore this problem.
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