Which expression is undefined? -8-(-8) -8-8 0-8 9-0​

In a singing competition, there are 150 participants. at the end of each round, 40% of the participants are eliminated. how many participants are left after n rounds?

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?

Susie wants to take her friend out for lunch.she wants to spend $9.75 each person. how much will she spend in all.