50 tickets need sold but only 9 have been sold what percent have been sold?

Can someone me i’m confused. will give brainliest and a whole bunch of points

The value of the expression 16-^3/4 8 1/8 -6 6 1/40 1/64

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”?