<h2><em><u>Solution</u></em> : </h2>
let the last number be x
we know,

So,





therefore, the last number is 10.
Base on the data you have given and with my calculation, i think the best value for Delta X and Dy is delta x = 2 and the DY = 1/2.I hope you are satisfied with my answer and feel free to ask for more if you have more clarifications and further questions
Answer:
1
Step-by-step explanation:
They will have games on the same day in 21 days