The number of ways, 5 boys and 4 girls can sit in a row so that either all the boys sit together or no two boys sit together, is -

Step-by-step solution

A : number of ways that all boys sit together =5! 5! B : number of ways if no 2 boys sit together =4! 5 ! A B = Required no. of ways =5! 5!+4! 5!=17280