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If x and y are prime numbers and x < y, which of the following cannot
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10 Jan 2022, 03:12
10 Jan 2022, 03:12
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Question Stats:
81% (01:25) correct
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If x and y are prime numbers and x < y, which of the following cannot be true?
x is even.
x + y is odd.
xy is even.
y + xy is even.
2x + y is even.
x is even.
x + y is odd.
xy is even.
y + xy is even.
2x + y is even.
Re: If x and y are prime numbers and x < y, which of the following cannot
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12 Jan 2022, 11:59
12 Jan 2022, 11:59
solution please.
Re: If x and y are prime numbers and x < y, which of the following cannot
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17 Jan 2022, 01:01
17 Jan 2022, 01:01
1
Ans: E => 2x + y is even.
necessarily, we need to check the option for two different conditions:
1st - when x is 2 (yes 2 is a prime number) and y is any other prime greater than 2 (lets take 3)
2nd - when x and y are any random primes (lets take 3 and 5)
now check the options and see for which both the conditions come out false:
(A) => x is even ; is true for condition - 1 but not for condition - 2
(B) => x + y is odd; is true for condition - 1 (2+3=5) but not for condition - 2 (3+5=8)
(C) => xy is even; is true for condition - 1 (2*3 = 6) but not for condition - 2 (3*5=15)
(D) => y + xy is even; is true for condition - 2 (((5 + (3*5)) = 20) but not for condition - 2 (((3 * (2*3)) = 18)
(E) => 2x + y is even; is false for condition - 1 (((2*2) + 3) = 7) it is also false for condition - 2 (((2*3) + 5) = 11)
thus, ans => E
necessarily, we need to check the option for two different conditions:
1st - when x is 2 (yes 2 is a prime number) and y is any other prime greater than 2 (lets take 3)
2nd - when x and y are any random primes (lets take 3 and 5)
now check the options and see for which both the conditions come out false:
(A) => x is even ; is true for condition - 1 but not for condition - 2
(B) => x + y is odd; is true for condition - 1 (2+3=5) but not for condition - 2 (3+5=8)
(C) => xy is even; is true for condition - 1 (2*3 = 6) but not for condition - 2 (3*5=15)
(D) => y + xy is even; is true for condition - 2 (((5 + (3*5)) = 20) but not for condition - 2 (((3 * (2*3)) = 18)
(E) => 2x + y is even; is false for condition - 1 (((2*2) + 3) = 7) it is also false for condition - 2 (((2*3) + 5) = 11)
thus, ans => E
