GMATPrepNow

If x > 0, b > a, and 2x + 5 < 3x + 1, then which of the following COULD be a value of x?
i) 4.39
ii) 7.17
iii) 9.27
A) i and ii only
B) ii and iii only
C) i and iii only
D) iii only
E) i, ii and iii
*kudos for all correct solutions
I. InequalitiesTriangle Side/Angle relationship: Larger angles' opposite sides are longer than
smaller angles' opposite sides
Although we can combine inequalities, calculating them separately
is just as quick and possibly less confusing.
(1) Inequality 1, given:
b > a The side opposite
b > side opposite
a\(4x-8>3x+1\)
\(x>9\)(2) Inequality 2, given:
\(2x + 5 < 3x + 1\)
\(x>4\)Inequality 1's lower limit in the range is 9
x MUST be greater than 9
That condition includes and satisfies Inequality 2
Any number greater than 9 is also greater than 4
By contrast, if x is between 4 and 9 (x >4 has lower limit 4),
then x is NOT greater than 9. Not valid.
x must be > 9
Only option iii) 9.27 works
Answer D
II. Inequalities - Number line
Range of solutions for x > 9 [in which (9) = not including 9]
<--0----------------------------(9)
-------------------->Range of solutions for x > 4
<--0--------(4)
--------------------------------------->The lower limit, 9, from the range in Inequality 1, makes the second range true.
x > 9, by definition, means x > 4. A number greater than 9 is also greater than 4
But 4 cannot be the lower limit for the range of solutions
That is,
x cannot lie between 4 and 9.
If x lies between 4 and 9, then x is not greater than 9
<--0--------(4)
---------------(9)
------------------>The range of solutions for x > 9 satisfies both conditions
The range of solutions for x > 4 does not satisfy the condition that x > 9
x > 9, is the only possibility, and
only option iii) 9.27, is > 9
Answer D