On a voyage to atlantis, ariel from the little mermaid decided to pick up shells so that she could make necklaces for her mermaid friends. she picked up 30 green shells, 35 blue shells, and 30 yellow shells. 17 of the green shells had some blue in them. 15 of the shells had both yellow and blue in them, and 10 of the shells had both yellow and green in them. if just one shell had all three colors in it, how many total shells did ariel pick up?

marco saved more.   he saved $35 more.

step-by-step explanation:

1+2+3+4+5+6+7+8+9+10 = 55

2*10 = 20

55-20 = 35

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.