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 |
If 0.01 mol of $\mathrm{P_4O_{10}}$ is removed from 0.1 mol, then the remaining molecules of $\mathrm{P_4O_{10}}$ will be:
Ratio of time required for 99% completion vs 90% completion of a first order reaction is: