​ I got this answer, but I'm not confident that its right...

√ 24x  * √ 18y  *  √ 15y  

2√ 6x  * 3√ 2y * √ 15y  

6 √  [ 6x * 2y * 15y ]

6 √  [ 180 * x * y^2 ]  

6 √  [ 36 * 5 * x * y^2 ]

36y√ [ 5x ]  ⇒  Correct  !!!