Okay so we know that there is 14 basketball cards, and it wants a ratio of basketball to all cards. So you just add up all the cards together.
45 + 21 + 20 + 14 = 100
So your current ratio is 14:100
Now to simplify it.
The only reasonable number to simplify it is by 2.
14/2 = 7 100/2=50
So your simplified ratio should be 7:50.