If a parakeet costs p dollars and a baby parrot costs d dollars, record using algebra: If I had $80.00 and bought 3 parakeets and 4 baby parrots, how much money do I have left?

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”?