:3. In a Public Health Service Study of 1964, a histogram was
plotted showing the number of cigarettes per day smoked by each
subject (male, current smokers), as shown in diagram ? on page ?
of the test.  The density is marked in parentheses.  The class
intervals include the right endpoint, not the left. <p>

The percentage who smoked ten cigarettes or less per day is
closest to <p>

a. 1.5%
 b. 15%
 c. 30%
 d. 50%
 e. 70%  <p>