Question

The average age of a number of persons in a group was calculated as 36 years, which was 4 years more than the correct average as there was an error in recording the age of two persons as 40 years 3 months and 33 years 5 months instead of 28 years 9 months and 20 years 11 months respectively. The number of persons in the group was?​

Answer 1

Answer:

6

Step-by-step explanation:

Let a and b be the total age, and number of people in the group respectively

Let average age be x ( Correct Case)

So, x = ( a/b )

Average age increases by 4 , when 2 people have their ages increased by 11.5 and 12.5 months.

So,

x + 4 = ( ( a + 11.5 + 12.5 ) / b )

= ( ( a +24 ) / b )

= a/b + 24/b

Replacing a/b by x

x + 4 = x + ( 24/b )

4 = 24/b

So,

b = 6