The number of emails a friend receive each day during last 20 days is shown below. what number of days she receive 19 or fewer e-mails in a day?
a.7
b. 11
c. 12
d. 15

To answer the problem just add the frequencies that correspond to email counts that are 19 or fewer. So you're adding the counts that correspond to 0-9 and 10-19. So the frequency of 0-9 is 4 and the frequency of 10 -19 is 7. So 4 + 7 = 11

step-by-step explanation:

the multiplicative inverse of a fraction a/b is b/a. for the multiplicative inverse of a real number, divide 1 by the number. for example, the reciprocal of 5 is one fifth 1/5 or 0.2, and the reciprocal of 0.25 is 1 divided by 0.25, or 4.