Answer: Bill has 12 cards
Alan and Calvin both have 19 cards each.'
Explanation:
Let x= Number of cards Bill has.
Then Alan has cards =
![2(1)/(2)x-11=(5)/(2)x-11](https://img.qammunity.org/2021/formulas/mathematics/middle-school/7kdrjecidp5s65p5rx1yc1wbp3jjlax82y.png)
Calvin has cards =
![1(1)/(2)x+1=(3)/(2)x+1](https://img.qammunity.org/2021/formulas/mathematics/middle-school/1wyh9lj1in2mlo3lh6nbix07yf1ndamej9.png)
Since Alan and Calvin has equal number of cards.
Then,
![(5)/(2)x-11=(3)/(2)x+1](https://img.qammunity.org/2021/formulas/mathematics/middle-school/fnqubvejl2qkksjafakkgeyimuulf8wrez.png)
![\Rightarrow\ (5)/(2)x-(3)/(2)x=1+11\\\\\Rightarrow\ (5-3)/(2)x=12\\\\\Rightarrow\ (2)/(2)x=12\\\\\Rightarrow\ x=12](https://img.qammunity.org/2021/formulas/mathematics/middle-school/cp040oalimr9z53m5wnohkjk5tlx6kofdh.png)
So, Bill has 12 cards
Then, Alan has cards =
![(5)/(2)(12)-11=30-11=19](https://img.qammunity.org/2021/formulas/mathematics/middle-school/694uhxlzvtmlc36ahm1wvx94wadthyu9ui.png)
Calvin has cards =
![(3)/(2)(12)+1=18+1=19](https://img.qammunity.org/2021/formulas/mathematics/middle-school/dgf6v7rm9ldaa2kllfikitr9mrfekwcu6g.png)
So, Alan and Calvin both have 19 cards each.