One sort of average problems includes the weighted normal - which is the normal of at least two terms that don't all have a similar number of individuals. To locate the weighted term, duplicate each term by its weighting factor, which is the quantity of times each term happens.

The equation for weighted normal is:

**Illustration: **
A class of 25 understudies took a science test. 10 understudies had a normal (number juggling mean) score of 80. Alternate understudies had a normal score of 60. What is the normal score of the entire class?

**Arrangement: **
Step 1: To get the aggregate of weighted terms, duplicate each normal by the quantity of understudies that had that normal and afterward total them up.

80 × 10 + 60 × 15 = 800 + 900 = 1700

Step 2: Total number of terms = Total number of understudies = 25

Step 3: Using the recipe

**Sample questions**
1) On a ferry, there are 50 cars and 10 trucks. The cars have an average mass of 1200 kg and the trucks have an average mass of 3000 kg. What is the average mass of all 60 vehicles on the ferry?

(A) 1200 kg

(B) 1500 kg

(C) 1800 kg

(D) 2100 kg

(E) 2400 kg

2) In Plutarch Enterprises, 70% of the employees are marketers, 20% are engineers, and the rest are managers. Marketers make an average salary of $50,000 a year, and engineers make an average of $80,000. What is the average salary for managers if the average for all employees is also $80,000?

(A) $80,000

(B) $130,000

(C) $240,000

(D) $290,000

(E) $320,000

3) At Didymus Corporation, there are just two classes of employees: silver and gold. The average salary of gold employees is $56,000 higher than that of silver employees. If there are 120 silver employees and 160 gold employees, then the average salary for the company is how much higher than the average salary for the silver employees?

(A) $24,000

(B) $28,000

(C) $32,000

(D) $36,000

(E) $40,000

4) In a company of only 20 employees, 10 employees make $80,000/yr, 6 employees make $150,000/yr, and the 4 highest-paid employees all make the same amount. If the average annual salary for the 20 employees is $175,000/yr, then what is the annual salary of each highest-paid employee?

(A) $250,000

(B) $300,000

(C) $350,000

(D) $400,000

(E) $450,000

5) In a certain apartment building, there are one-bedroom and two-bedroom apartments. The rental prices of the apartment depend on a number of factors, but on average, two-bedroom apartments have higher rental prices than do one-bedroom apartments. Let R be the average rental price for all apartments in the building. If R is $5,600 higher than the average rental price for all one-bedroom apartments, and if the average rental price for all two-bedroom apartments is $10,400 higher that R, then what percentage of apartments in the building are two-bedroom apartments?

(A) 26%

(B) 35%

(C) 39%

(D) 42%

(E) 52%

6) At a certain upscale restaurant, there just two kinds of food items: entrees and appetizers. Each entrée item costs $30, and each appetizer item costs $12. Last year, it had a total of 15 food items on the menu, and the average price of a food item on its menu was $18. This year, it added more appetizer items, and the average price of a food item on its menu dropped to $15. How many appetizer items did it add this year?

(A) 3

(B) 6

(C) 9

(D) 12

(E) 15