Mr. nelson used 3/8 of his money to buy some pens and 2/5 of the remainder to buy 2 notebooks. a notebook costs 3 times as much as a pen. how many pens did he buy?

9

Step-by-step explanation:

Call the Total Amount of money he had X.

Amount he used to buy pens: 3/8X

Amount of money left after buying pens: X - 3/8X = 5/8X

Amount he used to buy notebooks: 2/5 * 5/8X = 1/4X

1/4X or 2/8X for 2 notebooks, so if he spent 3/8X for notebooks, he would get 3 notebooks.

As a notebook cost 3 times a pens, so for 3/8X money, he bought 9 pens.

answer: just subtact the units and then add the non negative : happy to

step-by-step explanation:

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.