There are infinite equivalent expressions. Here are some:
1/5(m-100)
20(1/100m-1)
1/5m-(4•5)
If you expand any of these or any of the terms, you will get an equivalent expression. 
 
        
             
        
        
        
Answer:
The bulbs should be replaced each 1060.5 days.
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean  and standard deviation
 and standard deviation  , the zscore of a measure X is given by:
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:

How often should the bulbs be replaced so that no more than 1% burn out between replacement periods?
This is the first percentile, that is, the value of X when Z has a pvalue of 0.01. So X when Z = -2.325.




The bulbs should be replaced each 1060.5 days.
 
        
             
        
        
        
Answer:
889674568890
Step-by-step explanation:
I used a calculator :)
 
        
             
        
        
        
The nearest ten thousand is 20,000