Cheese sticks that were previously priced at "10 for $1" are now "2 for $1". Find each percent change.

Part 1 out of 2
Find the percent decrease in the number of cheese sticks you can buy for $1.

The percent decrease is

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”?