if a solution has a pH of 4 mix to a solution that has a pH of 9 what will be the pH of the mixed solution? will it be acidic or base? please show me how to calculate it.please i need the answer before tomorrow morning. thank you so much. I had been to other sites but i didn't understand it .please help and thank you so much!

Assuming that there is no interaction between the two solutions, all we can say with certainty is the pH is between 4 and 9. It depends on the nature of the solutions, their concentrations and the quantities of each. A pH of 7 is neutral, so you cannot tell if it will be acidic or base either.