George has three iron rods. Rod A is 7 feet long, rod B is 13 feet long, and rod C is 5 feet long. If the full length of each rod is used, can the three iron rods be placed together to form a triangle?
A.
yes, 13 - 7 > 5
B.
yes, 5 + 7 < 13
C.
no, 7 + 5 < 13
D.
no, 13 - 5 < 7

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”?