A shop recorded total sales of $2,000 on Monday. On Tuesday, its sales fell by 10%. On Wednesday, sales fell by another 20% compared with Tuesday. From Wednesday to Thursday, sales increased by an amount equal to 25% of Monday’s total sales. What is the net change, in dollars, in total sales from Monday to Thursday?

$60

Step-by-step explanation: The shop had $2,000 in sales on Monday. 

If it fell by 10% on Tuesday, then 2000 * 0.10 equals the percentage it dropped, so it dropped by $200. So they only had $1,800 in sales on Tues. 

If they fell by another 20% on Wednesday, 1,800 * 0.20 equals a $360 drop. Now we're at $1,440. 

The sales then increased by 25% of Monday's total # of sales. 25% of Monday's sales is 2,000 * 0.25 which equals a $500 increase. Now we're at $1,940. 

Now that we're done with everything, how far are we from the beginning? That's the net change. :) We began at $2,000 on Monday, and ended with $1,940 on Thursday. 2000 - 1940 is 60, so 60 = your net change. 

TLDR: Sold $2,000 on Mon, sold $1,800 on Tues, sold $1,440 on Wed, and then sold $1,940 on Thurs. The net change is $60.

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introduction, methodology, results, discussion

step-by-step explanation:

an observational study is one which consists of actual observation to record data and then analyse the data.

there are a number of factors that should be analyzed before starting an observational study.

the main four factors are:

i) introduction:   this should be analysed to check whether the purpose of the study is correctly established and the data recorded are appropriate for the study

methodology:   the method of collecting the data, such as whether randomly selected, and whether sample size matches with the population to be studied, whether questions asked are easy to answer by common men, etc.

results: then results such as summary of data with comments should be studied thoroughly

discussion:   the last is the discussion, this can be either by management people or persons who are all interested , etc.

b

step-by-step explanation: