In a certain chemical, the ratio of zinc to copper is 3 to 16. a jar of the chemical contains 736 grams of copper. how many grams of zinc does it contain?

The jar has 138 grams of zinc.

Solution:

Given that , In a certain chemical reaction, the ratio of zinc to copper is 3 to 16.  

A jar of the chemical contains 736 grams of copper.  

We have to find how many grams of zinc does it contain

Let "n" be the grams of zinc needed for 736 grams of copper  

Now, we know that,  

16 grams of copper ⇒ 3 grams of zinc

Then, 736 grams of copper ⇒ n grams of zinc

So, by criss cross multiplication,

16n = 3 x 736

16n = 2208

n = 138

Hence, the jar has 138 grams of zinc.

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.