Challenger App

No.1 PSC Learning App

1M+ Downloads
The average age of 20 boys in a class is 12 years. 5 new boys are admitted to the class whose average age is 7 years. The average age of the boys in the class becomes

A9.5 years

B8.2 years

C11 years

D12.5 years

Answer:

C. 11 years

Read Explanation:

New average age of class=20×12+5×7/25 =240+35/25 = 11 years


Related Questions:

The average weight of a group of 20 boys was calculated to be 65 kg and it was later discovered that the weight of a boy was misread as 76 kg instead of the correct weight 66 kg. The correct average weight was:
The average weight of three men A,B and C is 84 Kg. Another man D joins the group and the average now becomes 80 kg. if another man E whose weight 3 kg more than D replaces A then the average of B C D and E become 79 kg . What is the weight of A ?
In a class, there are 18 very tall boys. If these constitute three fourths of the boys and the total number of boys is two-thirds of the total number of Students in the class, what is the number of girls in the class ?
The average age of 5 boys is 16 yr, of which that 4 boys is 16 yr 3 months the age of the 5th boy is ?
image.png