how to form a quadractic equation for this question

Answer to your  question "One fourth of a herd of camels were seen in the forest. twice the square root of the herd gone to the muontain and the remaining 15camels were seen on the bank of a river . find the total number of camels." is follwing

Let there be x camels

 in forest = 1/4x

muontain = 2sqrt(x) remaining camels = 15
So x = 1/4x +2sqrt(x)+15 is required  equation which on simplification reduces.

9x²-424x+3600 = 0