Question - Vedclass

English

Gujarati

Hindi

4.Average

hard

The average weight of $45$ students in a class is $52\, kg.$ Five of them whose average weight is $48 \,kg$ leave the class and other $5\, students$ whose average weight is $54\, kg$ join the class. What is the new average weight (in $kg$ ) of the class

A

$52 \frac{1}{3}$

B

$52 \frac{1}{2}$

C

$52 \frac{2}{3}$

D

$52 \frac{3}{2}$

Solution

Average weight of $45$ students $=52 kg$

$\therefore$ Total weight $=45 \times 52 kg$

Weight of students left $=5 \times 48 kg$

Weight of students joined $=5 \times 54 kg$

New average weight $=\frac{45 \times 52-5 \times 48+5 \times 54}{45}$

$=52+\frac{5(54-48)}{45}$

$=52+\frac{30}{45}=52 \frac{2}{3} \,kg$

Std 13

Quantitative Aptitude

Share

Similar Questions

Average of $a, b$ and $c$ is $11 ;$ average of $c, d$ and $e$ is $17 ;$ average of $e$ and $f$ is $22$ and average of $e$ and $c$ is $17 .$ Find out the average of $a, b,$ $c , d , e$ and $f ?$

medium

The average age of a man and his two twin born on the same day is $30 \,year.$ The ratio of the ages of father and one son is $5: 2,$ what is the father's age in $year?$

medium

In a school with $600$ students, the average age of the boys is $12$ $years$ and that of the girls is $11\, years.$ If the average age of the school is $11 \,years$ and $9 \,months,$ then the number of girls in the school is

medium

Out of nine persons, eight persons spent $Rs. \,30$ each for their meals. The ninth one spent $Rs. \,20$ more than the average expenditure of all the nine. The total money spent by all of them was (in $Rs.$)

medium

If the average of the ages of Rakesh and Mohan is $15,$ average of the ages of Mohan and Ramesh is $12$ and the average of the ages of Rakesh and Ramesh is $13,$ then the age of Mohan, is?

medium