Word Problem on Weighted Average

Q. In a class, the average age of $20$ boys is $16$ years and the average age of $18$ girls is $15$ years. The average age of all the students is .

Q. In a company, the weighted average salary of the employees is $\$500$. The average salary of $25$ employees is $\$800$, while the average salary of the remaining employees is $\$600$. What is the total number of employees in the company?

1. $25$
2. $50$
3. $100$
4. $125$

Q. The average age of $20$ cows is $6$ years and the average age of $15$ goats is $5$ years. What is the average age of these animals?

1. $5.57\text{years}$
2. $7.57\text{years}$
3. $5\text{years}$

Q. pounds of mixed nuts worth $\$4.75\text{/lb}$ should be combined with $10\text{lb}$ of dried fruits worth $\$5.50\text{/lb}$ to make a trail mix that would sell for $\$4.95\text{/lb}$.

Q. The teacher divided the students of grade $7$ into $4$ groups and conducted a test. The number of students in the $4$ groups formed were $12,16,13$, and $15$ and the corresponding average score of these groups were $23,25,19$, and $27$.

What will be the weighted average score of the students of grade $7$?

1. $19$
2. $23.71$
3. $27.21$
4. $25$