The average of $41$ consecutive odd numbers is $49$. What is the largest number?

In a coconut grove,$(x+2)$ trees yield $60$ nuts per year,$x$ trees yield $120$ nuts per year,and $(x-2)$ trees yield $180$ nuts per year. If the average yield per year per tree is $100$,find the value of $x$.

The average of the first nine prime numbers is

Out of three numbers,the first is twice the second and is half of the third. If the average of the three numbers is $56$,the three numbers in order are

The average temperature of the first $4 \, \text{days}$ of a week is $38.6^{\circ} \text{C}$ and that of the last $4 \, \text{days}$ is $40.3^{\circ} \text{C}$. If the average temperature of the entire week is $39.1^{\circ} \text{C}$, find the temperature on the $4^{th} \, \text{day}$ (in $^{\circ} \text{C}$).

The mean weight of $34$ students of a school is $42\, kg$. If the weight of the teacher is included, the mean weight increases by $400\, g$. Find the weight (in $kg$) of the teacher.