Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized for You

we will pick new questions that match your level based on your Timer History

Track Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Thank you for using the timer!
We noticed you are actually not timing your practice. Click the START button first next time you use the timer.
There are many benefits to timing your practice, including:

Re: If y is the smallest positive integer such that 3,150 [#permalink]
28 Jan 2012, 17:00

2

This post received KUDOS

Expert's post

1

This post was BOOKMARKED

mrwaxy wrote:

If y is the smallest positive integer such that 3,150 multiplied by y is the square of an integer, then y must be A. 2 B. 5 C. 6 D. 7 E. 14

Detailed explanation would be appreciated.

3,150=2*3^2*5^2*7, now 3,150*y to be a perfect square y must complete the odd powers of 2 and 7 to even number (perfect square has even powers of its primes), so the least value of y is 2*7=14. In this case 3,150y=(2*3^2*5^2*7)*(2*7)=(2*3*5*7)^2=perfect \ square.

Re: If y is the smallest positive integer such that 3,150 [#permalink]
30 Jan 2012, 08:46

factorise 3150, to find out the missing doubles... 3150 = 5x5x3x3x2x7... so 2x7=14... when multiplied to 3150, will make it a perfect square... answere is E

Re: If y is the smallest positive integer such that 3,150 [#permalink]
13 Jun 2013, 01:07

1

This post received KUDOS

mrwaxy wrote:

If y is the smallest positive integer such that 3,150 multiplied by y is the square of an integer, then y must be

A. 2 B. 5 C. 6 D. 7 E. 14

In such questions we need to break the number into the smallest possible prime factors. So the smallest prime factors of 3150 are: 315*10=63*5*2*5=7*9*5*2*5=7*3*3*5*2*5. In order to get a square of an integer we have to have at least two identical primes. In our case we have 3*3 and 5*5 corresponding to this condition but not 2*7 so our smallest number should be 14.

Answer is E _________________

If you found my post useful and/or interesting - you are welcome to give kudos!

Re: if y is the smallest positive interger such that 3150 multip [#permalink]
29 Aug 2013, 00:35

kumar83 wrote:

if y is the smallest positive interger such that 3150 multiplied by y is the square of an interger, that Y must be

A) 2 B) 5 C) 6 D) 7 E) 14

Kindly Explain.

3150 =2*3^2*5^2*7 For it to be perfect square all the prime number should be least raised to the power 2 in 3150 ...only 2 and 7 needs to be multiplied so that all prime will be raised power 2 hence least value of 4y = 2*7 = 14

hence E _________________

When you want to succeed as bad as you want to breathe ...then you will be successfull....

Re: If y is the smallest positive integer such that 3,150 [#permalink]
22 Jul 2014, 03:18

Hello,

can anyone help me with this type of question? I don't get it why the remaining numbers, 7 and 2, are the smallest positive integer y. Which chapter in the MGMAT books should i restudy to deal with this kind of problem? I don't understand the explanation in the OG which says: "To be a perfect square, 3,150y must have an even number of each of its prime factors."

Re: If y is the smallest positive integer such that 3,150 [#permalink]
22 Jul 2014, 03:31

Expert's post

lou34 wrote:

Hello,

can anyone help me with this type of question? I don't get it why the remaining numbers, 7 and 2, are the smallest positive integer y. Which chapter in the MGMAT books should i restudy to deal with this kind of problem? I don't understand the explanation in the OG which says: "To be a perfect square, 3,150y must have an even number of each of its prime factors."