In a lottery, 5 balls are selected from a bin of twenty balls numbered 1 through 20. (The order doesn't matter.) Professor Luckless always guesses a 5-ball combination that includes her lucky number 7, and does not include her unlucky number 13. How many different days can she play the lottery without repeating a 5-ball guess?

5,10,15,20

Step-by-step explanation:

5,10,15,20

a

step-by-step explanation:

chemists are often responsible for designing a chemical reaction and analyzing the products obtained from it. one significant part of designing a chemical reaction is determining the amount of each reactant that is needed and the amount of each product that will be produced. in order to do so, chemists use stoichiometry, the quantitative relationships between reactants and products.