Hint for first one:
The X's denote the direction of the feild. The magnetic feild lines go into the page. Think of it like an arrow, a circle means out while a x means into in these type of questions.
F=BIL
where B is magnetic feild strength mesured in Teslas
I is current mesured in Ampres
L is length mesured in metres
F is force mesured in Newton's
Second one:
When it says 'In the plane of the page' it means its running in line with the page. So its not going in or out of the page,either top to bottom, left to right etc
Use the right hand rule to find the direction of the current so you can do A. It will allow you to do b, which uses a similar equation to the above