1. A snack bar sells two sizes of snack packs. A large snack pack is $8, and a small snack pack is $4. In one day, the snack bar sold 20 snack packs for a total
of $120. Write a system to determine how many small and large snack packs the
snack bar sold. Then find how many large and small snack packs the snack bar
sold?

answer

system : 8L+ 4S = 120

               L + S = 20

There are 10 small packs and 10 large packs

step by step answer :

to form the two systems, we have to determine the catagories of the 2 equations : one for money and one for the no of packs

after forming the two equations we simply put the numbers in the same order put above on the calculator ( mode 5:1) and the calaculator will answer it in seconds . 10 small packs and 10 large packs.

To  check your answer , substitute the letters with their values and if both equations gave you the same value at the end then your answer is correct!  

the answer is 31.27mph