BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Gmat Prep (Product of least and greatest)

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Master | Next Rank: 500 Posts
Posts: 446
Joined: Thu Jul 26, 2007 1:07 pm
Thanked: 6 times

Gmat Prep (Product of least and greatest)

by dferm » Fri Aug 15, 2008 8:17 am
If n is the product of the least and the greatest of 6 consecutive integers, what is the value of n?

(1) The greatest of the 6 consecutive integers is 20.
(2) The average(arithmetic mean) of the 6 consecutive integers is 17.5.

Can someone help me on this question....
Top
Source: — Data Sufficiency |
Master | Next Rank: 500 Posts
Posts: 315
Joined: Thu Aug 17, 2006 10:43 pm
Thanked: 23 times

by Suyog » Fri Aug 15, 2008 12:23 pm
IMO D.
Top
Master | Next Rank: 500 Posts
Posts: 446
Joined: Thu Jul 26, 2007 1:07 pm
Thanked: 6 times

by dferm » Fri Aug 15, 2008 12:27 pm
How did u arrive to your answer.?
Top
Legendary Member
Posts: 1153
Joined: Wed Jun 20, 2007 6:21 am
Thanked: 146 times
Followed by:2 members

by parallel_chase » Fri Aug 15, 2008 12:34 pm
The answer is indeed D.

6 consecutive integers, n = lowest integer * greatest integer

Statement I

the greatest number is 20
the smallest number = 20-6 +1 = 15
n= 15*20

sufficient.


Statement II

The mean is 17.5

In an evenly spaced set MEAN = MEDIAN
The integers above the median = 18,19,20
The integers below the median = 15,16,17
n=15*20

Sufficient.

Hence D is the answer.
Top
Master | Next Rank: 500 Posts
Posts: 446
Joined: Thu Jul 26, 2007 1:07 pm
Thanked: 6 times

by dferm » Fri Aug 15, 2008 12:44 pm
Thanks...Pretty nice explanations....I GOT IT....
Top
Master | Next Rank: 500 Posts
Posts: 328
Joined: Thu Aug 07, 2008 5:25 pm
Location: Philadelphia
Thanked: 4 times
GMAT Score:550

by Abdulla » Wed Dec 03, 2008 7:36 pm
parallel_chase wrote:The answer is indeed D.

6 consecutive integers, n = lowest integer * greatest integer

Statement I

the greatest number is 20
the smallest number = 20-6 +1 = 15
n= 15*20

sufficient.


Statement II

The mean is 17.5

In an evenly spaced set MEAN = MEDIAN
The integers above the median = 18,19,20
The integers below the median = 15,16,17
n=15*20

Sufficient.

Hence D is the answer.
hey Parallel chase..
how you come up with the smallest number = 20-6 +1 = 15 ??
Abdulla
Top
User avatar
Legendary Member
Posts: 2134
Joined: Mon Oct 20, 2008 11:26 pm
Thanked: 237 times
Followed by:25 members
GMAT Score:730

Re: Gmat Prep (Product of least and greatest)

by logitech » Wed Dec 03, 2008 9:08 pm
dferm wrote:If n is the product of the least and the greatest of 6 consecutive integers, what is the value of n?

(1) The greatest of the 6 consecutive integers is 20.
(2) The average(arithmetic mean) of the 6 consecutive integers is 17.5.

Can someone help me on this question....
First number : k
Last number : k+5

St1)

k+5 = 20

k = 15 SUF

St2)

k+....k+5/6 = 17.5

k = 15 SUF
LGTCH
---------------------
"DON'T LET ANYONE STEAL YOUR DREAM!"
Top
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Wed Dec 03, 2008 9:13 pm
Stmt I

If the greatest number is given then we can get to the lowest then to n

SUFF

Stmt II

Avg is 17.5 Sum=105

Since they are consecutive integers only one unique set of 6 consecutive integers will give a sum of 105. Even if one number changes the sum will be different

Hence we can find the smallest and greates then n from here

Hope I dint miss something here.

D)
Top
User avatar
Legendary Member
Posts: 2134
Joined: Mon Oct 20, 2008 11:26 pm
Thanked: 237 times
Followed by:25 members
GMAT Score:730

by logitech » Wed Dec 03, 2008 9:21 pm
cramya wrote:Stmt I

If the greatest number is given then we can get to the lowest then to n

SUFF

Stmt II

Avg is 17.5 Sum=105

Since they are consecutive integers only one unique set of 6 consecutive integers will give a sum of 105. Even if one number changes the sum will be different

Hence we can find the smallest and greates then n from here

Hope I dint miss something here.

D)
GOOD NEWS CRAMYA!! YOU DID NOT MISS ANYTHING BRO!! YAY :)

Funny..
LGTCH
---------------------
"DON'T LET ANYONE STEAL YOUR DREAM!"
Top
Legendary Member
Posts: 621
Joined: Wed Apr 09, 2008 7:13 pm
Thanked: 33 times
Followed by:4 members

by vittalgmat » Wed Dec 03, 2008 10:17 pm
Let the numbers be a, a+1, a+2, a+3, a+4, a+5.

given a(a+5) = n ; what is n?

stmt 1:
a+5 = 20
so a = 15.
From this, we can get all the numbers of the sequence. Any property can be
ascertained.
Sufficient.


stmt2)
avg of the 6 numbers is 17.5.
ie (a+ a+5)/2 = 17.5 (coz avg of sequence of n consecutive # = (1st# + last#)/2

= 2a +5 = 17.5.
So a can be calculated.
Sufficient.

D
Top
Master | Next Rank: 500 Posts
Posts: 328
Joined: Thu Aug 07, 2008 5:25 pm
Location: Philadelphia
Thanked: 4 times
GMAT Score:550

by Abdulla » Wed Dec 03, 2008 10:22 pm
Good Explanations guys..

I have one more question..

In consecutive integers, why don't we consider the question as an even/odd consecutive integers also ??
Abdulla
Top
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Wed Dec 03, 2008 11:12 pm
In consecutive integers, why don't we consider the question as an even/odd consecutive integers also ??

Among any 2 or more consecutive integers it will have atleast one even and one odd(may be more of each also depends on the number of consecutive intgers and whether u start wioth even or odd as the first in the list).


Consecutive even integers or Consecutive odd intgers are not the same as consectuive intgers and hence we dont bring that in to the picture


P.S (fyi)

In general

consecutive integers: x, x+1, x+2 ....... or k, k+1,k+2... whatever variable u pick

consecutive odd or consecutive even integers can both be represented as

x,x+2,x+4......

Eg: x=1 it will 1,3,5 - consecutive odd
x=2 it will be 2,4,6 - consecutive even

Hope this helps!

Regards,
CR
Top
Master | Next Rank: 500 Posts
Posts: 328
Joined: Thu Aug 07, 2008 5:25 pm
Location: Philadelphia
Thanked: 4 times
GMAT Score:550

by Abdulla » Wed Dec 03, 2008 11:14 pm
Thanks Cramya
Abdulla
Top
Legendary Member
Posts: 2467
Joined: Thu Aug 28, 2008 6:14 pm
Thanked: 331 times
Followed by:11 members

by cramya » Wed Dec 03, 2008 11:16 pm
No problem!

Also keep in mind that 0 is even

(and)

Odd and even intgers can be negative also.

-3,-1,1,3 are also consectuive odd intgers

-2,0,2,4 are also consecutive even integers
Top
Junior | Next Rank: 30 Posts
Posts: 28
Joined: Sun Aug 31, 2008 11:21 am
Location: Oxford

Re: Gmat Prep (Product of least and greatest)

by vbcannon » Wed Dec 03, 2008 11:19 pm
dferm wrote:If n is the product of the least and the greatest of 6 consecutive integers, what is the value of n?

(1) The greatest of the 6 consecutive integers is 20.
(2) The average(arithmetic mean) of the 6 consecutive integers is 17.5.

Can someone help me on this question....
I guess this is where being simple minded helps but I took this approach.

(1) Highest number =20 so : 20 ; 19 ; 18 ; 17 ; 16 ; 15

since I knew I could find all six integers, I knew I could find the sum of the least and the greatest. I guess I missed that the consecutive integers could be even but I didn't think about that because I figured they would specify.

(2) The average of the 6 consecutive integers is 17.5 so I wrote down 17.5 and circled it and then wrote 17 to the left of it, 18 to the right of it, 16 to left of 17 and 19 to right of 18, and so on. This gave me a 15-20. So i figured I would be able to solve the equation by just having this option.

So that is how I chose D.

Was that luck that I came up with that answer? Should I be considering the even numbers as integers or even other patterns?
Top
Post new topic Post Reply