You made 3/20 of the 400 cards, which is 60 cards.
Answer: 2/3x-12=48
remember that less than means it goes to the back
First combine like terms on each side so
8x = -7x
then move -7x
so x=0
2 1/4 times 3 1/9
Make the fractions into decimals
So now it’s 2.25 times 3.11...
Multiply that to get 6.99 but since the 3.11... is a repeated sequence you would round it to 7, which is your answer!