The sparkling house cleaning company has cleaned 28 houses this week. if this number represents 40% of the total number of houses the company is contracted to clean, how many total houses wil the company clean by the end of the week?

28 number of Houses = 40% of the total houses the cleaning company needs to clean in a week.
Find the total number of houses do the cleaning company needs to clean in a week>
=> 28 number of houses / 40%
=> 28 / 0.4
=> 70
Thus, the total number of houses that a cleaning company needs to clean in the whole week is 70 houses.
Since they already cleaned 40% of it, which is 28, thus, they still need to clean 42 more.

The difference is 5,100m?