The average age of a class of 20 pupils is 11years.if each of the 5 oldest pupils in the class is 14years old what is the average age of the remaining 15 pupils
To find the average age of the remaining 15 pupils, we first need to calculate the sum of their ages.
The sum of the ages of the 5 oldest pupils is 5 * 14 = 70 years old.
The sum of the ages of the entire class is 20 * 11 = 220 years old.
To find the sum of the remaining 15 pupils, we subtract the sum of the ages of the 5 oldest from the sum of the ages of the entire class: 220 - 70 = 150 years old.
Finally, we divide the sum of the remaining 15 pupils' ages by the number of pupils (15) to find the average age: 150 / 15 = 10 years old.
So, the average age of the remaining 15 pupils is 10 years old.
To find the average age of the remaining 15 pupils, we need to first calculate the sum of their ages.
Step 1: Calculate the sum of the ages of the 5 oldest pupils:
5 oldest pupils x age of 14 years each = 5 x 14 = 70 years
Step 2: Calculate the sum of the ages of all 20 pupils:
Average age x number of pupils = Total age
Average age x 20 pupils = Total age
11 years x 20 pupils = Total age
Total age = 220 years
Step 3: Calculate the sum of the ages of the remaining 15 pupils:
Total age - sum of ages of the 5 oldest pupils = sum of ages of the remaining 15 pupils
220 years - 70 years = 150 years
Step 4: Calculate the average age of the remaining 15 pupils:
Average age of the remaining 15 pupils = sum of ages of the remaining 15 pupils / number of remaining pupils
Average age of the remaining 15 pupils = 150 years / 15 pupils
Average age of the remaining 15 pupils = 10 years
Therefore, the average age of the remaining 15 pupils is 10 years.