GRE Math Problem 72

Compare two values:

Column A	Column B
The average (arithmetic mean) of all the positive multiples of 5 less than 26	The average (arithmetic mea: of all the positive multiples of 7 less than 26

Solution for Questions GRE Analytical Problem 5, Part 2

Question IV

If S appears on a panel, that panel must consist of at least how many professors?

(A) 3

(B) 4

(C) 5

(D) 6

(E) 7

C6: S => (NV)

And there are no more conditions that require more members.

Answer (A) 3

Question V

Which of the following is an acceptable group of professors for a panel?

(A) M, N, Q, R – violates C2: !(MNR)

(B) M, Q, R,T – is quite acceptable

(C) M, R, T, U  – violates C5: R <=> Q

(D) M, S, U, V – violates C6: S => (NV)

(E) N,R,T,U – violates C5: R <=> Q

Answer (A) M, N, Q, R

Question VI

Which of the following groups of professors can form an acceptable panel by doing nothing more than adding one more professor to the group?

(A) M, R, T

C5:R <=> Q

We must add Q and we’ll get an acceptable panel

(B) N,Q,M

C5:R <=> Q

We must add R/ But that panel would violate

C2: !(MNR)

(C) Q,R, S

According to

C6: S => (NV)

We must add both N and V

(D) Q,R,V

C4: V=>(MS) or (MU) or (SU) or (MSU)

We must add at least two members

(E) V, R, N

C4: V=>(MS) or (MU) or (SU) or (MSU)

We must add at least two members

Answer (A) M, R, T

Question VII

Of the group N, S, T, U, V, which professor will have to be removed to form an acceptable panel?

(A) N

(B) S

(C) T

(D) U

(E) V

This panel violates

C1:!(NTU)

So, we must remove one of them.

But the presence of N and V is required by S

C6: S => (NV)

Then, we must remove T

Answer (C) T

Solution for Questions GRE Analytical Problem 5, Part 1

Solution for Questions GRE Analytical Problem 5:

Let’s fix the conditions:

C1: N, T, and U cannot all appear on the same panel.

!(NTU)

In another form it can be written:

(NT)=>!V

(NU)=>!T

(TU)=>!N

C2: M. N, and R cannot all appear on the same panel.

!(MNR)

In another form it can be written:

(MN)=>!R

(MR)=>!N

(NR)=>!M

C3: Q and V cannot appear on the same panel.

!(QV)

In another form it can be written:

Q <=> !V

V <=> !Q

C4: If V appears on a panel, at least two professors of the trio M, S, and U must also appear on the panel.

V=>(MS) or (MU) or (SU) or (MSU)

Or, equivalent to this:

(!M!S) or (!M!U) or (!S!U)=>!V

C5: Neither R nor Q can appear on a panel unless the other also appears on the panel.

R <=> Q

From this follows:

!R <=> !Q

C6: If S appears on a panel, both N and V must also appear on that panel.

S => (NV)

Then,

!N or !V => !S

Now we can proceed to question solving.

Question I

Which of the following CANNOT appear on a panel with R?

(A) M

(B) N

(C) Q

(D) S

(E) T

C5: R <=> Q

C4: Q <=> !V

C6: !N or !V => !S

So, professor S CANNOT appear on a panel with R

Answer (D) S

Question II

Exactly how many of the professors can appear on a panel alone?

(A) 1

(B) 2

(C) 3

(D) 4

(E) 5

C4: V=>(MS) or (MU) or (SU) or (MSU)

Professor V can’t appear on a panel alone.

C5: R <=> Q

Professor’s R and Q can’t appear on a panel alone.

C6: S => (NV)

Professor S can’t appear on a panel alone.

So, only four of them can.

Answer (D) 4

Question III

If neither V nor N appears on a panel, then which of the following must be true?

(A) M appears on the panel.

(B) Q appears on the panel.

(C) T appears on the panel.

(D) S does not appear on the panel.

(E) U does not appear on the panel.

C6: !N or !V => !S

Answer (D) S does not appear on the panel.

Analytical Problem 5

The planning committee of an academic conference is planning a series of panels using eight professors, M, N, Q, R, S, T, U, and V. Each panel must be put together in accordance with the following conditions:

N, T, and U cannot all appear on the same panel.

M. N, and R cannot all appear on the same panel.

Q and V cannot appear on the same panel.

If V appears on a panel, at least two professors of the trio M, S, and U must also appear on the panel.

Neither R nor Q can appear on a panel unless the other also appears on the panel.

If S appears on a panel, both N and V must also appear on that panel.

Question I

Which of the following CANNOT appear on a panel with R?

(A) M

(B) N

(C) Q

(D) S

(E) T

Question II

Exactly how many of the professors can appear on a panel alone?

(A) 1

(B) 2

(C) 3

(D) 4

(E) 5

Question III

If neither V nor N appears on a panel, then which of the following must be true?

(A) M appears on the panel.

(B) Q appears on the panel.

(C) T appears on the panel.

(D) S does not appear on the panel.

(E) U does not appear on the panel.

Question IV

If S appears on a panel, that panel must consist of at least how many professors?

(A) 3

(B) 4

(C) 5

(D) 6

(E) 7

Question V

Which of the following is an acceptable group of professors for a panel?

(A) M, N, Q, R

(B) M, Q, R,T

(C) M, R, T, U

(D) M, S, U, V

(E) N,R,T,U

Question VI

Which of the following groups of professors can form an acceptable panel by doing nothing more than adding one more professor to the group?

(A) M, R, T

(B) N,Q,M

(C) Q,R, S

(D) Q,R,V

(E) V, R, N

Question VII

Of the group N, S, T, U, V, which professor will have to be removed to form an acceptable panel?

(A) N

(B) S

(C) T

(D) U

(E) V

Solution for GRE Math Problem 71:

Peter's grade > Victor's grade

Georgette’s grade > Victor's grade

We can’t determine, which of these grades is higher

Answer:D

GRE Math Problem 71

Peter's grade was higher than that of Victor.and Victor's grade was less than that of Georgette.

Column A	Column B
Georgette's grade	Peter's grade

Solution for GRE Math Problem 70:



Area=length x width

New Area=length x (1.25 width) = 1.25 (length x width) = 1.25 Area

Area will increase by 25%.


Answer:(A) 25%

GRE Math Problem 70

If the width of a rectangle is increased by 25% while the length remains constant, the resulting area is what percent of the original area?

(A) 25% 

(B)75% 

(C) 125% 

(D)225%

(E) Cannot be determined from the information given.

Solution for GRE Math Problem 69:

At what rate is the water filling the tank?
800-300=500 cubic feet
How many minutes will it take to completely fill a water tank?
3,750:500 = 7.5 minutes = 7 min. 30 sec.

Answer:(C) 7 min. 30 sec.

GRE Math Problem 69

How many minutes will it take to completely fill a water tank with a capacity of 3,750 cubic feet if the water is being pumped into the tank at the rate of 800 cubic feet per minute and is being drained out of the tank at the rate of 300 cubic feet per minute?
(A) 3 min. 36 sec.
(B) 6 minutes
(C) 7 min. 30 sec.
(D) 8 minutes
(E) 1,875 minutes


Solution for GRE Math Problem 68:

The legs of triangle BCE equal to the sides of the square ABCD. So, its area is the half of the area of ABCD. Thus,  the area of ABCD is 16

Answer:(C) 16