To find the equation of the time they spent we need to use the:
Where m is the slope and (x1,y1) is a point of the table.
We can find the slope with:
Using the first two points on the table we have:
Now plugging the values of the slope and the first point into the equation we have that:
Therefore the equation that represents the time they spent is:
where x is the number of people they survey and y is the time it takes.