Answer: He practiced 90 minutes on Friday.
Explanation:
Let be "w" the amount of minutes Julian practiced the clarinet on Wednesday and "f" the amount of minutes Julian practiced the clarinet on Friday.
Convert the total time he praticed on Wednesday and Friday to minutes. Since
, 2 hours and 15 minutes is:
Set up a System of equations:
Applying the Substitution Method, you can subsitute the second equation into the first equation and solve for "w":
Finally, substitute this value into the second equation to find "f":
Therefore, he practiced 90 minutes on Friday.