Which statement is correct?

(2.06x 10-(1.88x10-) <

1.88 x 10--769x102

2.3x10-5

(2.06 x 10-21.88 x 10-

1

7.69x 10-2

2.3x10-5

(2.06 x 10-2)(1.88 x 10-')> 7.59x1

100x

(2.06 x 10-2)(1.88 x 10-1.

^ ^

7.69x 10-2

23x105

23x10-6

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”?