Solution :
It is given that the time required by a company to built the fencing = 4 hours
The length of fenced completed in 1 hour = 1.6 mile
Now by using the double number line to find the length of the fence, we would :
-- We have to draw two parallel straight lines.
-- Let the 1st line represents the time measured in hours and the 2nd line represents the distance or length measured in miles.
-- Mark four marks of equal spacing in both the line so that each mark represents 1 hour in the 1st line and each mark in the 2nd line represents the corresponding lengths.
-- Now in hour, they completed 1.6 miles, therefore from the double number line, we can see that in 4 hours, they completed 4.6 miles of fencing.
Hence the length is 4.6 miles.
