find the HCF and LCM of 92 and 510 by the method of prime factorization hence verify that HCF into SCM equal to product of two given number​

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”?