10 because you know that the decimal moves one to the left if you are dividing by ten and one to the right if you are multiplying by ten.
Check your work. 0.32 divided by 10 is 0.032
This just wants the derivative which you can solve for.
You can do this using a negative expononet or using ...the rational rule forget its name*.... you shoudl get 9000/(t+12)^2
*Quotient rule
Okay so there is enough material for 12 people for 10 days but there is 15 of them we have to see how long they can last with that material i am going to need more info to complete this but let me do you an example for some help lets say a whole 10 day package is 10 crackers so if there is 12 packages then that means there is 120 crackers if there were 12 people every one would get 10 but there is 15 so we need to divide 120 and 15 which comes out to 8 so that means every body gets eight crackers whick also means they only last eight days but sense the question is not complete i can not help you much i nee the amount that is in the packages that they purchased