Find score from mean practice

A swimmer logged $20$, $24$, $18$, $22$, and $26$ laps on five days of practice. On a sixth day, she swam $x$ laps. The mean number of laps per day over all six days is $23$. What is the value of $x$?

On four science quizzes, Priya earned scores of $85$, $92$, $78$, and $88$. On a fifth quiz, her score was $x$. The mean score on all five quizzes is $87$. What is the value of $x$?

In three bowling games, Alex rolled scores of $142$, $156$, and $138$. In a fourth game, the score was $x$. The mean score over the four games is $150$. What is the value of $x$?

During a fitness challenge, four teammates completed $15$, $20$, $18$, and $22$ push-ups in the first four rounds. In the fifth round, one teammate completed $x$ push-ups. The mean number of push-ups per round is $19$. What is the value of $x$?

A student read $30$, $45$, $35$, $40$, $50$, and $25$ pages on six days of a reading challenge. On a seventh day, she read $x$ pages. The mean number of pages read per day over all seven days is $38$. What is the value of $x$?

A musician practiced piano for $40$, $55$, and $50$ minutes on three days. On a fourth day, the practice time was $x$ minutes. The mean practice time over the four days is $48$ minutes. What is the value of $x$?

Maria earned history quiz scores of $70$, $82$, $74$, and $90$ on four quizzes. On a fifth quiz, her score was $x$. The mean score on all five quizzes is $81$. What is the value of $x$?

At trivia night, a team answered $6$, $8$, $7$, and $9$ questions correctly in the first four rounds. In the fifth round, the team answered $x$ questions correctly. The mean number of correct answers per round is $8$. What is the value of $x$?