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For the positive integers q, r, s, and t, the remainder when [#permalink]
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TechWithNoExp wrote:
For the positive integers q, r, s, and t, the remainder when q is divided by r is 7 and the remainder when s is divided by t is 3. All of the following are possible values for the product rt EXCEPT:

A. 32
B. 38
C. 44
D. 52
E. 63


Great question!!

USEFUL PROPERTY:
When positive integer N is divided by positive integer D, the remainder R is such that 0 ≤ R < D
For example, if we divide some positive integer by 7, the remainder will be 6, 5, 4, 3, 2, 1, or 0
Conversely, if I know that, when k is divided by w, the remainder is 5, then I know that w must be greater than 5

The remainder when q is divided by r is 7
This tells us that r is greater than 7

s is divided by t is 3
This tells us that t is greater than 3

Now check the answer choices...

A) 32
Is it POSSIBLE for rt to equal 32?
Yes, if r = 8 and t = 4, then rt = 32
ELIMINATE A

B) 38
Is it POSSIBLE for rt to equal 38?
NO.
There are only two ways to write 38 as the product of POSITIVE INTEGERS:
i) (2)(19) = 38
ii) (1)(38) = 38
If r is greater than 7 and t is greater than 3, there's no way that one of the values (r or t) can equal 1 or 2.

Answer: B

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Originally posted by BrentGMATPrepNow on 28 Aug 2018, 13:55.
Last edited by BrentGMATPrepNow on 03 Jan 2021, 07:40, edited 1 time in total.
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Re: For the positive integers q, r, s, and t, the remainder when [#permalink]
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krishnasty wrote:
For the positive integers q, r, s, and t, the remainder when q is divided by r is 7 and the remainder when s is divided by t is 3. All of the following are possible values for the product rt EXCEPT

32
38
44
52
63


r>=8 And t>=4

32=8*4(Possible)
38=19*2 OR 38*1, none of which is possible because 2 AND 1 are both less than 4 OR 8.
44=11*4
52=13*4
63=9*7

Ans: "B"
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Re: For the positive integers q, r, s, and t, the remainder when [#permalink]
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Jp27 wrote:
For the positive integers q, r, s, and t, the remainder when q is divided by r is 7 and the remainder when s is divided by t is 3. All of the following are possible values for the product rt EXCEPT

32
38
44
52
63

OA

From the question we know that r >= 8 and s >=4

So A is possible, from there how to proceed?

Cheers


\(32 = 2^5\)
\(38 = 2^1 * 19^1\)
\(44 = 2^2 * 11^1\)
\(52 = 2^2 * 13^1\)
\(63 = 3^2 * 7^1\)
All options other than B can be represented as a product of two numbers one being greater than or equal to 4 and the other being greater than or equal to 8.

So, answer should be B

Kudos Please... If my post helped.
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Re: For the positive integers q, r, s, and t, the remainder when [#permalink]
TechWithNoExp wrote:
For the positive integers q, r, s, and t, the remainder when q is divided by r is 7 and the remainder when s is divided by t is 3. All of the following are possible values for the product rt EXCEPT:

A. 32
B. 38
C. 44
D. 52
E. 63


r>7
t>3
rt factor can't be<4
38 has two sets of factors: 1*38*and 2*19
1 and 2 are both<4
B
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Re: For the positive integers q, r, s, and t, the remainder when [#permalink]
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The remainder when q is divided by r is 7 and the remainder when s is divided by t is 3 and we need to find all of the following are possible values for the product rt EXCEPT

Theory: A number, when divided by a number k, can give remainder from 0 to k-1

The remainder when q is divided by r is 7
=> r > 7
=> Possible values of r are 8, 9 , 10, 11,...

The remainder when s is divided by t is 3
=> t > 3
=> Possible values of t are 3, 4, 5, 6,...

Let's see which all options we can make for rt

A. 32
r = 8, t = 4 => rt = 32 => POSSIBLE

B. 38
r = 19, t = 2 => rt = 38 But t cannot be 2 => NOT POSSIBLE

In test, we don't need to solve further but I am solving to complete the solution.

C. 44
r = 11, t = 4 => rt = 44 => POSSIBLE

D. 52
r = 13, t = 4 => rt = 52 => POSSIBLE

E. 63
r = 9, t = 7 => rt = 63 => POSSIBLE

So, Answer will be B
Hope it helps!

Watch the following video to learn the Basics of Remainders

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