Answer:
The minimum guaranteed mileage is 
Step-by-step explanation:
From the question we are told that
The mean is 
The standard deviation is 
Generally for the probability to be 4% the minimum guaranteed mileage is evaluated as



=> 
=> 
From the z table, the critical value corresponding to 0.96 to the left of the curve is

So

=> 
In this problem, we have the following variables:
e: The weekly earnings of a salesperson
s: sales in a given week
A salesperson earns $200 a week plus a 4% commission on her sales, that is, she earns:
<em>$200 plus 0.04 of her sales in a given week</em>
In a mathematical model, this is given by:
e = 200 + 0.04s
2000x(100%-29%)=1420
1420 of them did not have pets