If x and y are prime numbers, which of the following CANNOT be the sum of x and y ?
Solution
Correct Answer: Option D
let ,
2+3 = 5 --- (1)
2+7= 9 ----- (2)
2+11 = 13---- (3)
21+2 = 23 ----- (4)
Here , we can see that the equation of 1,2,3 can be written as the sum of two prime numbers .
Now, the equation of 4 is 23=2+21. Since 21 is not a prime then 23 cannot be written as the sum of two prime numbers .
2+3 = 5 --- (1)
2+7= 9 ----- (2)
2+11 = 13---- (3)
21+2 = 23 ----- (4)
Here , we can see that the equation of 1,2,3 can be written as the sum of two prime numbers .
Now, the equation of 4 is 23=2+21. Since 21 is not a prime then 23 cannot be written as the sum of two prime numbers .
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