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Re: If x and y are positive integers such that y is a multiple of 5 and 3x [#permalink]
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09 Feb 2018, 17:09
Can someone pls verify if this method will work for all similar question types? This is the way I approached as well wvu wrote: I approached this in a different style I think than the other posters  is this way correct as well?
First, 200 factors down to \(2^3 * 5^2\)
Looking at the information we know that from the equation \(3x + 4y\), where y is a multiple of 5, we have the factors of \(2^2\) (from the 4), 3, and 5. Given this, we can then determine that we need one more factor of both 2 and 5. E  10 is the only answer choice that provides those two factors.



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Re: If x and y are positive integers such that y is a multiple of 5 and 3x [#permalink]
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10 Feb 2018, 01:37
mrdlee23 wrote: Can someone pls verify if this method will work for all similar question types? This is the way I approached as well wvu wrote: I approached this in a different style I think than the other posters  is this way correct as well?
First, 200 factors down to \(2^3 * 5^2\)
Looking at the information we know that from the equation \(3x + 4y\), where y is a multiple of 5, we have the factors of \(2^2\) (from the 4), 3, and 5. Given this, we can then determine that we need one more factor of both 2 and 5. E  10 is the only answer choice that provides those two factors. We know that  \(3x + 4y = 200, y = 5m\) \(3x + 20m = 200\) \(x = \frac{10(20  m)}{3}\) So, x has to be multiple of 10.
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Re: If x and y are positive integers such that y is a multiple of 5 and 3x [#permalink]
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12 Feb 2018, 04:38
mrdlee23 wrote: Can someone pls verify if this method will work for all similar question types? This is the way I approached as well wvu wrote: I approached this in a different style I think than the other posters  is this way correct as well?
First, 200 factors down to \(2^3 * 5^2\)
Looking at the information we know that from the equation \(3x + 4y\), where y is a multiple of 5, we have the factors of \(2^2\) (from the 4), 3, and 5. Given this, we can then determine that we need one more factor of both 2 and 5. E  10 is the only answer choice that provides those two factors. Since y is a factor of 5, 4y will end in 0. So get the sum of 200, 3x should end in 0 as well. So x should be a multiple of 10.
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Re: If x and y are positive integers such that y is a multiple of 5 and 3x [#permalink]
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16 Apr 2018, 00:59
Abhishek009 wrote: AbdurRakib wrote: If x and y are positive integers such that y is a multiple of 5 and 3x + 4y = 200, then x must be a multiple of which of the following? A) 3 B) 6 C) 7 D) 8 E) 10 OG 2017 New Question Plug in values and check  Let y = 5 ; 3x + 4y = 200 So, 3x + 20 = 200 Or, x = 60 ( Options C & D rejected , Left with options A, B & E ) Let y = 20 ; 3x + 4y = 200 So, 3x + 80 = 200 Or, x = 40 ( Options A &B rejected , Left with option E ) Hence, answer will be optin (E)Hey, Abhishek009! 40 is also a multiple of 8, option D. So we still have D and E remaining.



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Re: If x and y are positive integers such that y is a multiple of 5 and 3x [#permalink]
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16 Apr 2018, 01:19
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advait92 wrote: Hey, Abhishek009! 40 is also a multiple of 8, option D. So we still have D and E remaining. Hey advait92 , As Abhishek009 has explained, we have already rejected option D when we substituted y = 5 in the equation. Remember for a "MUST" be true question, it should work for all the scenarios but we are not getting x a multiple of 8 whenever we have y = 5. Hence, D cannot be the answer. Does that make sense?
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Re: If x and y are positive integers such that y is a multiple of 5 and 3x [#permalink]
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16 Apr 2018, 02:00
abhimahna wrote: advait92 wrote: Hey, Abhishek009! 40 is also a multiple of 8, option D. So we still have D and E remaining. Hey advait92 , As Abhishek009 has explained, we have already rejected option D when we substituted y = 5 in the equation. Remember for a "MUST" be true question, it should work for all the scenarios but we are not getting x a multiple of 8 whenever we have y = 5. Hence, D cannot be the answer. Does that make sense? Hey abhimahna! Thank you for bringing this to my notice.




Re: If x and y are positive integers such that y is a multiple of 5 and 3x
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