Missed Work Hours Caused by One of a Class of Industrial

Short Answer

Missed work hours caused by one of a class of industrial accidents has a probability density function $f ( t ) = \frac { 1 } { 8 } e ^ { - t } + \frac { 3 } { 8 } e ^ { - t / 2 } + \frac { 1 } { 24 } e ^ { - t / 3 }$ where t is measured in hours.
-What proportion of these accidents result in 5 or fewer missed work hours?
Enter just a real number to two decimal places.