The product of two natural numbers is 19. The sum of the reciprocal of its square is Choices:	A) 361/362	B) 362/361	C) 360/359	D) 359/360	E) None of these
Explanation:   Let the number be a and b. Then,   ab = 19 =&gt; a = 1, b = 19   So, 1/a2 + 1/b2 = (a2 + b2)/a2b2   = (12 + 192)/(1 x 19)2 = 362/361   Answer: Option 362/361
<result>B</result>
The product of two natural numbers is 19. The sum of the reciprocal of its square is