GMAT 800 - Toughest GMAT Questions

A set of numbers has the property that for any number t in the set, t + 2 is in the set. If –1 is in the set, which of the following must also be in the set?

I. –3 II. 1 III. 5

A. I only
B. II only
C. I and II only
D. II and III only
E. I, II, and III

Solution

Series property: t => t+2.

(Note: for any given number N, ONLY N + 2 is compulsory. N - 2 is not a necessity as N could be the first term...this can be used as a trap.)

Given: -1 belongs to the series. => 1 => 3 =>5. DOES NOT imply -3.

Hence, II and III

Correct...

Two missiles are launched simultaneously. Missile 1 launches at a speed of x miles per hour, increasing its speed by a factor of Sqrt(x) every 10 minutes (so that after 10 minutes its speed is x*sqrt(x) , after 20 minutes its speed is x*sqrt(x)*sqrt(x) , and so forth. Missile 2 launches at a speed of y miles per hour, doubling its speed every 10 minutes. After 1 hour, is the speed of Missile 1 greater than that of Missile 2?

1)  x = sqrt(y)
2)  x > 8

(A) Statement (1) ALONE is sufficient to answer the question, but statement (2) alone is not.
(B) Statement (2) ALONE is sufficient to answer the question, but statement (1) alone is not.
(C) Statements (1) and (2)...

The organizers of a week-long fair have hired exactly five security guards to patrol the fairgrounds at night for the duration of the event. Exactly two guards are assigned to patrol the grounds every night, with no guard assigned consecutive nights. If the fair begins on a Monday, how many different pairs of guards will be available to patrol the fairgrounds on the following Saturday night?

A) 9
B) 7
C) 5
D) 3
E) 2

Answer Below

This question is not as complicated as it may initially seem. The trick is to recognize a recurring pattern in the assignment of the guards.

First, we have five guards (let's call them a, b, c, d,...

The line represented by the equation y = 4-2x  is the perpendicular bisector of line segment RP. If R has the coordinates (4, 1), what are the coordinates of point P?
(A) (–4, 1)
(B) (–2, 2)
(C) (0, 1)
(D) (0, –1)
(E) (2, 0)
 
Answer Below

First, rewrite the line y = 4-2x  as  y = -2x +4 . The equation is now in the form   where m represents the slope and b represents the y-intercept. Thus, the slope of this line is -2 .

By definition, if line F is the perpendicular bisector of line G, the slope of line F is the...

For a circle with center point P, cord XY is the perpendicular bisector of radius AP (A is a point on the edge of the circle). What is the length of cord XY?

(1) The circumference of circle P is twice the area of circle P.

(2) The length of Arc XAY = 2Pi/3

(A) Statement (1) alone is sufficient, but statement (2) alone is not sufficient.
(B) Statement (2) alone is sufficient, but statement (1) alone is not sufficient.
(C) BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
(D) Each statement ALONE is sufficient.
(E) Statements (1) and (2) TOGETHER are NOT sufficient.


Answer Below

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