Question

The arithmetic mean in a measure of central tendency and is popularly known as mean. Arithmetic mean is obtained by dividing the sum of the values of all items of a series by the number of items of that series. Normally, arithmetic mean is denoted by $\overline{X}$ which is red as '$X$ bar'. It can be computed for unclassified or ungrouped data or individual series as well as classified or grouped data or discrete or continuous series. A person walks $27$ km at a speed $3$ km per hour and again walks $24$ km at a speed of $4$ km per hour. What is the average speed in km per hour?

• A. $5$ km/hour
• B. $3.4$ km/hour
• C. $6$ km/hour
• D. $6.8$ km/hour

Answer 1

The correct option is B $3.4$ km/hour

Speed in km/hour (X)	Time (W)	Distance (WX)
3	27/3 $=$ 9	27
4	24/4 $=$ 6	24
	$\sum W=$ 15	$\sum WX=$ 51

Average speed $\left(X_w\right)=\frac{Totaldistance}{Totaltime}=\frac{\sum WX}{\sum W}=\frac{51}{15}$
$=3.4km/hour$