In a set of three variables, the average of the first two variables is greater than 2, the average of the last two variables is great than or equal to 3 , the average of the first and third variable is 4.Which of the following could be the average of the three variables?
A)1
B)1.5
C)2
D)3
E)3.5
How can i easily solve this problem? Can some experts help?
OA E
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In a set of three variables, the average of the first
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Average = (a + b + c)/3lheiannie07 wrote:In a set of three variables, the average of the first two variables is greater than 2, the average of the last two variables is great than or equal to 3 , the average of the first and third variable is 4.Which of the following could be the average of the three variables?
A)1
B)1.5
C)2
D)3
E)3.5
How can i easily solve this problem? Can some experts help?
OA E
(1) (a + b)/2 > 2
(2) (b + c)/2 >= 3
(3) (a + c)/2 = 4
Multiply all of the above by 2 on each side.
(1) (a + b) > 4
(2) (b + c) >= 6
(3) (a + c) = 8
Sum (1), (2) and (3) --> this must be greater than 18
(a + b) + (b + c) + (a + c) > 18
2(a + b + c) > 18
(a + b + c) > 9
(a + b + c)/3 > 3
E. 3.5 is the only answer which is greater than 3.
Answer is E
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Jeff@TargetTestPrep
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We can let the three variables be a, b and c. So we have:lheiannie07 wrote:In a set of three variables, the average of the first two variables is greater than 2, the average of the last two variables is great than or equal to 3 , the average of the first and third variable is 4.Which of the following could be the average of the three variables?
A)1
B)1.5
C)2
D)3
E)3.5
(a + b)/2 > 2
a + b > 4
and
(b + c)/2 ≥ 3
b + c ≥ 6
and
(a + c)/2 = 4
a + c = 8.
If we add up these three inequalities/equations, we have:
2a + 2b + 2c > 18
a + b + c > 9
(a + b + c)/3 > 3
The only number is greater than 3 is 3.5, thus it's the answer.
Answer: E
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