The cost of 355 ml can of juice is $1.25 in vending machine. a 1.89 l carton of the same juice cast $3.89 at the grocery store. 1: hou much would you save per ml if you bought juice from the grocery store instead of the vending machine? (hint: 1 l = 1000 ml)

To solve this you need to calculate the cost per milliliter of both juices.
355ml costs 1.25. So if you divide the 1.25 by 355ml you will get the cost of 1 ml
The second you will have to convert L to ml by multiplying the L by 1000 (move decimal 3 places right)
use this value to calculate same as before.
find the difference between the two 1ml values to calculate your savings.

9/12 is the answer because 3/4 times 3 each is 9/12