It took Matt twice the time to drive from home to work as it took him to drive back home from work by the same route. If Matt averaged 30 miles per hour (mph) on his drive to work, his average speed for the entire round trip was A) 30 mph
B) 25 mph
C) 40 mph
D) 15 mph

C: 40 mph

Step-by-step explanation:

We are told that it took Matt twice the time to drive from home to work as it took him to drive from work to home.

This means;

2(time to drive from home to work) = time to drive from work to home

2(30) = time to drive from work to home

time to drive from work to home = 60 hr

We are told it took Matt 30 miles/hr to drive from home to work.

Thus;

Time from home to work = x/30 hours

Time to drive from work to home = x/60

Total distance = x + x = 2x

Thus,average speed = 2x/(x/30 + x/60) = 2x/(3x/60) = 120x/3x = 40 mph

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.

answer: asdfghjkl,mnbv

step-by-step explanation: