Researchers from a data analysis firm have found that the th

[neha24]

Researchers from a data analysis firm have found that the three most popular combinations --
1234, 1111, and 0000 -- account for close to 20 per cent of all four-digit passwords. The researchers
also found that every four-digit combination that starts with 19 ranks above the 80th percentile in
popularity, with those in the upper 1900s coming in the highest. Also quite common are
combinations in which the first two digits are between 01 and 12 and the last two are between 01
and 31.

If the statements above are true, which of the following must be true?

(A) The password 1922 will most likely be less popular than 1981
(B) The password 0123 will most probably be more common than 2331
(C) If a password was to be selected from a random list of 100 four digit passwords, there is a very high possibility that it will be 1234, 1111, or 0000
(D) One out of three four digit passwords will be 1234, 1111, or 0000
(E) Passwords starting with 19 are more popular than those starting with 21

[hemant_rajput]

Researchers from a data analysis firm have found that the three most popular combinations --
1234, 1111, and 0000 -- account for close to 20 per cent of all four-digit passwords. The researchers
also found that every four-digit combination that starts with 19 ranks above the 80th percentile in
popularity, with those in the upper 1900s coming in the highest. Also quite common are
combinations in which the first two digits are between 01 and 12 and the last two are between 01
and 31.

If the statements above are true, which of the following must be true?

(A) The password 1922 will most likely be less popular than 1981
(B) The password 0123 will most probably be more common than 2331
(C) If a password was to be selected from a random list of 100 four digit passwords, there is a very high possibility that it will be 1234, 1111, or 0000
(D) One out of three four digit passwords will be 1234, 1111, or 0000
(E) Passwords starting with 19 are more popular than those starting with 21

I go with E.

What is OA?

[Alina Ross]

Answer most porbable
A - The password 1922 will most likely be less popular than 1981
This is clear from point 2 that those in upper 1900 are more popular than those in lower 1900, hence A is correct answer.

B- No data to confirm the statement
C- not very clear with the given data
D- No stated fact
E - No data about passwords starting with 21

[sonalibhangay]

My Answer C.

[apoorva.rattan]

IMO E. Here is why I think it is E.

Choice A : I would eliminate this because question says "with those in the upper 1900s coming in the highest. "
Choice B : Difficult to say if this is true as question says "Also quite common are
combinations in which the first two digits are between 01 and 12 and the last two are between 01
and 31.". Thus, eliminating this.
Choice C : Those three combinations account for only about 20%. Therefore, the probability will not be high to make this option true.
Choice D: Again, the first statement in the argument makes this statement incorrect.
Choice E: I would pick this esp. because the question stem says "every four-digit combination that starts with 19 ranks above the 80th percentile in
popularity,"

OA ?

[venkat18290]

Hi

There is a close competition between A and E in my opinion.

Option A :The author says that the upper 1900 are more probable , i could not justify whether 1983 comes under upper 1900's they author could have meant the numbers between 1990-1999 or 1985-1999 , so there is a minute ambiguity with this option .

So i choose E .

GMAT guru's kindly let me know if there is any fault in the logic i used to eliminate the first option.

[himu]

Between[spoiler] A & E.[/spoiler]
Whats the source Neha ????[spoiler][/spoiler]

[srcc25anu]

argument:
- 1234, 0000 and 1111 - one out of 5 passwords will be one of these as they account for 20% of all passwords - ST1
- 19XX passwords ranks above 80th %ile in POPULARILTY (higher the last 2 digits, more POPULAR) - ST2
-Common combinations 01XX, 02XX, ... 12XX for 1st 2 digits and XX01, XX02 ... XX31 for last 2 digits - ST3

A. 1922 more likely less POPULAR than 1981
True from ST2
B. 0123 more common than 2331. No data to conform this.
C. the possibility to select 1234, 1111 or 0000 is 1 in 5. We dont know if we can define that as VERY HIGH possibility.
D. 1 out of 3 passwords will be 1234, 0000 or 1111. No, its 1 out of 5 passwords will be either of these 3 from ST1
E. Passwords with 19XX more popular than 21XX. we know high 19XX passwords more popular (from ST2) but in this case we dont know whether the last 2 digits is towards the high end or low end. Cant say for sure.

IMO A

[[email protected]]

In the argument it states that combinations with last two digits between 01 and 31 are more common. Doesn't that make 1922 more popular than 1981 in choice a?