In the three intersecting circles given below, the numbers in different sections indicate the number of persons speaking different languages. How many persons speak only two languages?
The following table shows the ages of the patients admitted in a hospital during a year. Find the mode and the median of these data.
\[\begin{array}{|c|c|c|c|c|c|c|} \hline Age (in years) & 5-15 & 15-25 & 25-35 & 35-45 & 45-55 & 55-65 \\ \hline \text{Number of patients} & \text{6} & \text{11} & \text{21} & \text{23} & \text{14} & \text{5} \\ \hline \end{array}\]
Find the mean and mode of the following data:
Class | 15--20 | 20--25 | 25--30 | 30--35 | 35--40 | 40--45 |
Frequency | 12 | 10 | 15 | 11 | 7 | 5 |
What is 'X' in the following table?