Product of two natural numbers is 17. Then, the sum of reciprocals of their squares is
Choices.
A) 290/289  B) 1/289  C) 290/90  D) 290/19  E) None of these
Explanation:   If the numbers are a, b, then ab = 17,   as 17 is a prime number, so a = 1, b = 17.   1/a2+1/b2=1/1(2)+1/17(2)   1/ 2+1/ 2= 
<gadget id="calculator">1/ 2+1/ 2</gadget>
<output>1</output>
1/1(2)+1/17(2)=290/289   Option 290/289
<result>A</result>
Product of two natural numbers is 17. Then, the sum of reciprocals of their squares is