Question

The Sparkling House Cleaning Company has cleaned 28 houses this week. If this number repesents 40% of the total number of houses the company is contracted to clean, how many total houses will the company clean by the end of the week?

Answer 1

`42` houses left, so `70` will be cleaned in total

Explanation:

If the company completed `28` houses so far (this is `40%` of the total number of houses), then they have to clean `70` houses within one week.

It means `x=100*28/40`

where, `x` is the total houses must be cleaned per week.

Then you can get `x=70`.

It means they have to clean `70-28=42` more houses by the end of week.

Your answer is `70` houses.

Answer 2

`70` houses in total for the week.

Explanation:

This can be answered by using direct proportion.
Any percent question can be done this way.

We know that `28` houses represent `40%`

We want to know the total number of houses - the `100%`

Write them as a proportion:

`x/100 = 28/40" "(larr"houses")/(larr "percent")`

`x = (28xx100)/40`

`x =70` houses

You could also write the proportion like this:

`"percents "40/100 = 28/x" houses"` which gives the same result:

`x=70` houses