R S Aggarwal and Veena Aggarwal Solutions for Exercise 1: EXERCISE 18A

Find the mean of:

all prime numbers between $50$ and $80$.

The number of children in $10$ families of a locality are

           $2,4,3,4,2,0,3,5,1,6$.

 Find the mean number of children per family.

The following are the numbers of books issued in a school library during a week:

$105,216,322,167,273,405\text{ and }346$ 

Find the average number of books issued per day.

The daily minimum temperature recorded $(\text{in} °\mathrm{F})$ at a place during six days of a week was as under:

$\begin{array}{|cccccc|}\hline \text{ Monday }& \text{ Tuesday }& \text{ Wednesday }& \text{ Thursday }& \text{ Friday }& \text{ Saturday }\\ 35.5& 30.8& 27.3& 32.1& 23.8& 29.9\\ \hline\end{array}$

Find the mean of the given data.

The mean weight of $6$ boys in a group is $48 \mathrm{kg}$. The individual weights of five of them are$51 \mathrm{kg}, 45 \mathrm{kg}, 49 \mathrm{kg}, 46 \mathrm{kg}\text{ and} 44 \mathrm{kg}$. Find the weight of the sixth boy in $\mathrm{kg}$. (Write the answer excluding unit)

The mean of the marks scored by $50$ students was found to be $39$. Later on it was discovered that a score of$43$ was misread as $23$. Find the correct mean in decimal form.

The mean of $24$ numbers is $35$. If $3$ is added to each number, what will be the new mean$?$

The mean of $20$numbers is $43$. If $6$ is subtracted from each of the numbers, what will be the new mean?