Consider the equation, x3+3px2+3qx+r=0 ......(I) Let the roots in HP be [2,3,6] So, x3−(2+3+6)x2+[2.3+2.6+3.6]x−2.3.6=0 ......(II) x3−11x2+36x2−36=0 Compare equation (1) and (2). 3p=−11 p=−
11
3
And, 3q=36 q=12 And, r=−36 Therefore, the correct option is (1).