What is PERS-91?

What is the volume of a cylinder of 15m an 4m? What is negative 2 minus 16? If a rectangle length is 4 and its height is 6 cm find area of rectangle and parameter of rectangle? Why is it called experimental probability? What do you mean by KPI? Can efficiency be more than 100 percent? How many seconds are in a day? What does it mean to be a problem solver? Area of 18 perimeter of 20? What is the temperature from 15 degrees Celsius to -5 degrees Celsius? How many weeks in one half of a year? Rectangular arrangement using 100 squares how many can you make? If you travel 45 mph and you reach your destination in 12 mins how many miles did you travel? Can a polygon have less than three vertices? What percent of a circle is 122 degrees? How many edges are in a octohedron? How can you write 76 in roman numerals? What is hyperbolic functions? Is the word Problem in the bible? What is the measure of an external angle of a regular pentagon?