If 225.00 yields 27.00 in x years as simple interest at the rate of 4% per annum find x

Solve the following pair of equations for x and y: ax/b_ by /a= a +b; ax - by = 2ab

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”?

Perry observes the opposite parallel walls of a room in how many lines do the plains containing the walls intersect