If 2x+y = 10, 2y+z = 20 and 2x+z = 30. Where x, y,and z are real number. What is the value of 2x ?  Choose the correct choice from the following choices.
A) 3/2  B) sqrt(15)  C) sqrt(6)/2  D) 15  E) 18
Explanation :   Let, 2x = a, 2y = b and 2z = c   Then from the question:   2x+y = 2x * 2y = ab = 10   Similarly, bc = 20 , ac = 30   ab/bc = 1/2   =&gt; a/c = 1/2   and ac = 30   (a/c)*ac = 1/2*30= 
<gadget id="calculator">1/2*30</gadget>
<output>15</output>
15   a= sqrt(15)   Answer : sqrt(15)
<result>B</result>
If 2x+y = 10, 2y+z = 20 and 2x+z = 30. Where x, y,and z are real number. What is the value of 2x ?