What is 255 x 270 + 460

The hawaiian alphabet has 12 letters. how many permutations are posible for each number of letters?

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.

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”?