So you're trying to identify how many packs of ice cream cones Jim needs to buy if he needs 120 in total. To find this, first you have to find what number times 20 would get you 120. Then, you muitiply 6 by 20 to make sure it's 120. Once you do, you have your final answer.
Therefore, Jim needs to buy 6 packs to have a total of 120 ice cream cones.
I hope this information was of any use to you.