If a·b·c·d=510, where a, b, c and d are positive integers, and a<b<c<d, which of the following could be the value of d−a? Choose the correct choice from the following answers.
A) 9 B) 10 C) 11 D) 13 E) 15
prime factorize : 510 = 2*3*5*17   Hence a = 2 and d = 17 .   Hence answer is  17 - 2= 
<gadget id="calculator"> 17 - 2</gadget>
<output>15</output>
15   Answer 15
<result>E</result>
If a·b·c·d=510, where a, b, c and d are positive integers, and a<b<c<d, which of the following could be the value of d−a?