The number of cells in a bacteria culture decreases 15% each hour. If there are 10,000 cells at 9am, how many cells will the culture have at 5pm?

Question

using expect rule and showing a table

Answer 1

Starting with 10,000 cells, you lose 15% in 1 hour, so make a table with time and number of cells, till you get to 5 pm and your answer. 

 

10.000 * 0.15 = 1,500 so 10,000 - 1500 = 8500 left at 10 am.  Then take .15 * that number and subtract from 8500.  8500 - 1275 = 7225 at 11 am....etc etc.

 

Just fill in the table.

 

Hope this helps!  Best wishes. 

Answer 2

no idea what expect rule is but the answer is easy...
10000 9am

8500 10am

7225 11am

6141 12pm

etc etc 

 

just take 10000 and multiply it by .85(which is 15% less then the previous number) over and over.