First, you have to find how many friends are playing. This can be found in the equation 5-3. Now you multiply by six to find the cost. If you chose C, that would be incorrect, because the () you would mltilply first (30) and then subtract 3 (27). You can also think of it as finding the cost of how much all of them want to play by using the distributive property, leaving you with 30 - 18, and subtract from there to get 12.
