I did not understand the function math at all.

I am bad with probability math so couldn't understand how to solve it.I could solve easy probability and combination problems.But here the mention of less than kind of confused me i think.

In the distance rate problem both the statements kind of seemed the same to me.

And I did not understand the circular gear problem at all.

When I see some maths in this forum I think to myself, this looks hard!!But if I really try I could solve some and the ones I cant solve, when I see the solution I feel like saying-that was easy,why didn't I get it!!I know most of the basic concepts but at 1st glance and within 2 minutes ,its hard for me to figure out how to solve it.I am quiet weak at probability maths, and if they even just word an easy question in a tricky way, I get lost!!!

These are GMAT prep questions and I know the answers but I have no idea how they got to those answers.And I thought this forum is the best place to get to know and learn how to solve such problems.

(Pleeeeeeeease help!!!!)