### The following table shows the number of working hours and the number of employees employed in a small scale industry $\begin{array}{|c|c|} \hline \text { No. of working hours } & \text { No. of employees } \\ \hline 3-5 & 7 \\ \hline 5-7 & 10 \\ \hline 7-9 & 18 \\ \hline 9-11 & 57 \\ \hline 11-13 & 14 \\ \hline 13-15 & 8 \\ \hline \end{array}$ The average number of working hours of an employee is.

A. 8.5 B. 9.5 C. 10.5 D. None of these Answer: Option B

### Solution(By Apex Team)

We have : $\begin{array}{|c|c|c|c|c|c|c|} \hline \text { Mean working hours } & 4 & 6 & 8 & 10 & 12 & 14 \\ \hline \text { No. of employees } & 7 & 10 & 18 & 57 & 14 & 8 \\ \hline \end{array}$ Sum of working hours of all the employees = (4 × 7 + 6 × 10 + 8 × 18 + 10 × 57 + 12 × 14 + 14 × 8) = (28 + 60 + 144 + 570 + 168 + 112) = 1082 Total number of employees = (7 + 10 + 18 + 57 + 14 + 8) = 114 ∴ Average number of working hours $\begin{array}{l}=\left(\Large\frac{1082}{114}\right)\\ =9.49\approx9.5\end{array}$

## Related Questions On Average

A. 20
B. 21
C. 28
D. 32

A. 18
B. 20
C. 24
D. 30

A. 10 years
B. 10.5 years
C. 11 years
D. 12 years

### If the arithmetic mean of 0, 5, 4, 3 is a, that of -1, 0, 1, 5, 4, 3 is b and that of 5, 4, 3 is c, then the relation between a, b, and c is.

A. a = b = c
B. a : b : c = 3 : 2 : 4
C. 4a = 5b = c
D. a + b + c = 12