The earning by washing four cars is $20 and this can be determined by using the unitary method.
Given :
You earn $35 for washing 7 cars.
The following steps can be used in order to determine the earning by washing four cars:
Step 1 - The unitary method can be used in order to determine the earning by washing four cars.
Step 2 - According to the given data, the earning by washing seven cars is $35.
Step 3 - So, the earning for washing four cars is given by:
[tex]=\dfrac{4}{7}\times 35[/tex]
Step 4 - Simplify the above expression.
[tex]=\dfrac{140}{7}[/tex]
= $20
So, the earning by washing four cars is $20.
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