What comes in 15s?

What type of function has a graph with a series of unconnected points? How many times can a human blink in one minute? What is the pirimeter of a circle? What is the probability of rolling a number less than 3 on a 6-sided number cube numbered from 1 to 6? What unit would be best to use for measuring the wight of a stapler? How many square feet is a 27 inch diameter minus a 24 inch diameter interior circle? Decimal equivalent to 5.300? What is Cos Theta minus Cos Theta? How many nickels add up to1 million? What is noticeable about the sum in the multiples of 9? What fraction is 0.75 percent? What is the variance of 4 7 9 9 11? What is the highest common factor of 66 and 99? How long is a km in miles? What is the partial product for 543 times 6? What equation represents a line parallel to the line y5x-2? What is a half of roman numeral DX? How many twelfths are equal to two sixths? What is 35 out of 60 percent? What is -5d plus 40 equals 5d?