2. I am a 4-digit number. My ones digit is the highest one-digit number. My hundreds digit is 3 less than my ones digit. My
thousands digit is 2 more than my hundreds digit. My tens
digit is the number which means nothing. What number am I?​

:24% of students in a class are girls. if there are less than 30 students in this class, how many students are there? how many girls are there?

Last month, a 770 g box of cereal was sold at a grocery store for $3.10. however, this month, the cereal manufacturer launched the same cereal in a 640 g box, which is being sold at $2.50. what is the percent change in the unit price?

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