23. a tour bus averaged 50 miles per hours
between two cities on the first leg of
a trip and 45 miles per hour on the
return trip. the return trip took
hour longer. find the distance between
the two cities.

The distance between the cities is 50*4.5 = 225 miles.

Step-by-step explanation:

Let "t" be the time spent on the first leg at the average speed of 50 miles per hour.

Then (t+0.5) is the time spent on the returning trip at the average speed of 45 miles per hour.

Since the distance is the same in both directions, you have an equation

50*t = 45*(t+0.5).

Simplify and solve it for "t".

50t = 45t + 22.5,

5t = 22.5

Divide both sides by 5

t = 22.5/5

= 4.5.

Thus we found the time spent at the speed 50 mph. It is 4.5 hours.

Thus the distance between the cities is 50*4.5 = 225 miles

< 4, -5>

step-by-step explanation:

starting from g. we move 4 right and then 5 down to get to h. that means the vector is < 4, -5>

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.