Some businessmen and businesswoman were surveyed about their appointment calendars. Of the surveyed business people, 139 said they keep their business appointments on an electronic calendar, 56 keep their appointments on a paper calendar, and 23 keep both a paper calendar and an electronic calendar. Three respondents do not keep a calendar. A. How many business professionals were surveyed

that is the sum

step-by-step explanation:

there are no other answers without knowing the variables values

d

step-by-step explanation:

sites:

the system of inequalities is

step-by-step explanation:

step 1

find the equation of the dashed line

we have the points

(0,0) and (3,1)

the line passes through the origin, so, is a direct variation

find the slope

the equation of the dashed line is

the solution of the inequality a s the shaded area above the dashed line

therefore

the equation of the inequality a is

step 2

find the equation of the solid line

we have the points

(4,0) and (0,4)

find the slope

the equation of the solid line is

the solution of the inequality b s the shaded area below the solid line

therefore

the equation of the inequality b is

step 3

the system of inequalities is