An orchestra has 100 musicians 4/10 of them play string instruments-violin , viola, cellodouble bass , guitar, lute, and harp. What decimal is equivalent to 4/10 ?

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”?