Average age
There are 20 students in the class. Several are 12 years old, and others are 13 years old. Find out how old is twelve when the average age of a class is:
a) 12.5 years
b) 12.75 years
c) 12.3 years
d) 12.35 years
a) 12.5 years
b) 12.75 years
c) 12.3 years
d) 12.35 years
Correct answer:

Tips for related online calculators
Looking for help with calculating arithmetic mean?
Looking for a statistical calculator?
Need help calculating sum, simplifying, or multiplying fractions? Try our fraction calculator.
Do you have a linear equation or system of equations and looking for its solution? Or do you have a quadratic equation?
Looking for a statistical calculator?
Need help calculating sum, simplifying, or multiplying fractions? Try our fraction calculator.
Do you have a linear equation or system of equations and looking for its solution? Or do you have a quadratic equation?
You need to know the following knowledge to solve this word math problem:
We encourage you to watch this tutorial video on this math problem: video1
Related math problems and questions:
- Fifteen
Fifteen students had an average age of 12 years. When the class teacher came to see them, their average increased by exactly one year. How old was the teacher?
- Everyone's 81021
There are 10 students in the drama club. We count everyone's age in whole years. The average age of the girls is 12.25 and the boys 12.5, and the average age of all is 12.3. How many girls and how many boys are there in the class?
- Troops
There are two leaders in the tourist group, with an average age of 30 years, and several children with an average age of 10 years. The total age of the group is 12 years. How many children are in the group?
- Marks at school
There are 30 students in the class. Five students in the class had a mark of three or triple at the end of the math certificate, and the other students had a mark of one or two. The average mark in all students' mathematics in the class at the end of the
- Employees 70614
The company has 18 employees aged 26-52. The age groups of the employees are: 3 employees aged 52 years, 2 aged 32 years, 1 ... 26 years old, 5 ... 36 years old, 4 ... 45 years old, and 3 ... 50 years old. Determine the median.
- Everyone 63334
There are three times more children in the gym than adults. The average age of adults is 44 years. What is the average age of children if the total average age of everyone in the gym is 20?
- Average height
In a class are 34 students. The average height of the students is 165 cm. What will be the average height of students in the classroom when two pupils, tall 176 cm and 170 cm, move from this school/class? The average height in meters of all the students i
- Mini-survey
In the mini-survey of our class about the popularity of individual subjects, it turned out that 11.1% of pupils like mathematics, 18.5% enjoy languages, 30.4% of pupils like physical education, and the remaining 12 pupils have several popular subjects. Ho
- Big family
A certain number of people met at the family celebration - their average age was three times the number present. Then came my grandfather, who was 75 years old, and the average age was again three times the number present. How many people are celebrating
- Happy marriage
Jan and Marienka have been living in a happy marriage for several years. Jan's age is written in the same numbers as Marienka, only in reverse order. Their ages differ by just a fifth of Marienka's age. Jan is older. How old is Jan, and how many are Marie
- Coach
The average age of 24 players and a coach of one team is 24 years. The average age of players without a coach is 23 years. How old is the coach?
- Standard deviation
Find the standard deviation for the dataset (grouped data): Age (years); No. Of Persons 0-10 ; 15 10-20 ; 15 20-30 ; 23 30-40 ; 22 40-50 ; 25 50-60 ; 10 60-70 ; 5 70-80 ; 10
- Twenty-three-year-old 6317
The average age of the first five hockey players was 22 years. The coach replaced the twenty-three-year-old player with a younger one, which lowered the average age of the first five hockey players to 21 years. How old is the new player?
- Ages in
The ages of the 10 teachers of a School are 32, 41, 67, 55, 23, 25, 28,40, 22, 35. Find out the range of the age of teachers.
- There 11
There are 50 pupils in the class. Out of this number, 1/10 speak French only, and 4/5 of the ten speak French and English. If the rest speak English only, find the number of students who speak only English.
- Students 34
Students were surveyed as part of a Statistics project to determine if younger adults are more likely to have tattoos. The results are listed in the two-way table below: age; At least one tattoo; No tattoo; Row totals Age 18 - 29; 165 ; 342; 507 Age 30 -
- Large family
The average age of all family members (children, mother, father, grandmother, grandfather) is 29 years. The average age of parents is 40 years, grandparents 66 years, and all children are five years. How many children are there in this family?