50 POINTSSS..I WILL MARK BRAINLIEST, RATE, AND THX FOR WHOEVER ANSWERS FIRST .can someone put these 2 together?

Acomputer store bought a program at a cost of $10 and sold it for $13. find the percent markup

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”?

Here is my question! jayne is studying urban planning and finds that her town is decreasing in population by 3% each year. the population of her town is changing by a constant rate.true or false?