5. Each dimensional analysis problem has taken you 1.5 minutes to complete. How many dimensional analysis problems could you complete in 6 weeks of Chemistry class?

Step-by-step explanation:

So we're trying to get from minutes to weeks.  The time intervals in question are:

Minutes -> Hours -> Days -> Weeks

So we set up our dimensional analysis.  We're solving for amount of problems, so that goes in the numerator of the first fraction:

Now we want to know how many minutes in an hour, so we multiply by the next fraction:

After that, we want to know how many hours in a day:

and how many days in one week:

To solve the dimensional analysis problem, we multiply across the top of the entire expression, then divide across the bottom.  So:

1 * 60 * 24 * 7 = 10,080

And then divide that by the bottom:

10,080 / 1.5 / 1 / 1 / 1 = 6,720

So you can solve 6,720 problems in one week.  Multiply that by six and we get your

40,320 dimensional analysis problems can be completed in 6 weeks of Chemistry class.

b. astronomers

if you are saying purchasing 3 social media ads and one newspaper ad counts as one purchase then there are:

6 purchases

if you are asking how many of each then:

18 social media ads

6 newspaper ads