Which of the following could be the sum of the reciprocals of two different prime numbers?  Choose the most appropriate option.
A) 7/13
B) 10/12
C) 11/30
D) 23/50
E) 19/77
Here, the condition is that there should be two different prime nos.   A 13 = 13 x 1 ( 1 is not a prime number)   B 21 = 7 x 3 ( both 7 and 3 are prime nos)   C 30 = 10 * 3 or 5* 6 ( It can be written both ways, but 10 and 6 are not prime nos)   D 50 = 10 * 5 ( 10 is not a prime number)   E 77 = 11 * 7 ( both are prime numbers)   Options A, C, D are eliminated.   We are left with options B and E.   1/11 + 1/7 = 18/77 and not 19/77. Hence this option is eliminated.   Option 10/12 is the correct
<result>B</result>
Which of the following could be the sum of the reciprocals of two different prime numbers?