Me with math, worth 10 points! : d

Apinhole camera is made out of a light-tight box with a piece of film attached to one side and pinhole on the opposite side. the optimum diameter d(in millimeters) of the pinhole can be modeled by d=1.9[ (5.5 x 10^-4) l) ] ^1/2, where l is the length of the camera box (in millimeters). what is the optimum diameter for a pinhole camera if the camera box has a length of 10 centimeters

The difference between two numbers is one. three times the larger number minus two times the smaller number is 9. what are the two numbers

In a class of 77, there are 44 students who play soccer. if the teacher chooses 33 students, what is the probability that none of the three of them play soccer?