So we have 2 variables here: tacos and orders of nachos.
When we translate the paragraphs into equation:

Now, in this situation we can make use the elimination method by converting 3n to -27n.

Add both equations:

So we find that one taco costs $2.75.
We can plug this into any of the first two equations to find n:

So one order of nachos cost $1.40.
Answer: The 8 pound bag
Step-by-step explanation: you divide 9.45 by 5 and you get the unit rate of 1.89 and then you divide 13.68 by 8 and you get the unit rate of 1.71 which means the 8 pound bag is cheaper.
Use PEMDAS to solve this so
4000(1.0005) 52 • 15 =
4002 (52) • 15 = 3,121,500