The average age of25 boys in a class decreases by 6 months when a new

1.	The average age of25 boys in a class decreases by 6 months when a new boy takes the place of a 20year old boy. Find out the age of new boy?
Answer» Let age of the new boy was X. Age decreased = 6 months = 6/12 = 1/2 years Now, we have formula for this type of questions, Number of members in the Group * age decreased = difference in ages of boy in and boy out. 24 * (1/2) = 20 -X X = 8 years. Thought process method: Total age decreased = 6 *24 = 145 months = 12 years. It means the difference of the ages between boy in and out would be = 20 - 12= 8 years answer is not correct from given options:a. 7b. 6c. 6.5d. 7.5

The average age of25 boys in a class decreases by 6 months when a new boy takes the place of a 20year old boy. Find out the age of new boy?

Answer»

Let age of the new boy was X.

Age decreased = 6 months = 6/12 = 1/2 years

Now, we have formula for this type of questions,

Number of members in the Group * age decreased = difference in ages of boy in and boy out.

24 * (1/2) = 20 -X

X = 8 years.

Thought process method:

Total age decreased = 6 *24 = 145 months = 12 years.

It means the difference of the ages between boy in and out would be = 20 - 12= 8 years

answer is not correct from given options:a. 7b. 6c. 6.5d. 7.5