Three times four, plus two to the third power

14400

Step-by-step explanation:

We have 2 groups of 5 elements each

there is a condition all boys will be ahead always, therefore  in the group of boys there are

5!  =  5*4*3*2*1  =  120 differents form

And the girls at the same time can change theirs places according to

5! =  120

Then total ways for the line up in the conditions of the statement of the problem are

T = 120*120  

14400