Find the greatest number of four digits which when divided by $10, 15, 21$ and $28$ leaves $4, 9, 15$ and $22$ as remainders,respectively.

The areas of three fields are $165 \ m^2$,$195 \ m^2$,and $85 \ m^2$ respectively. In each of the fields,a flower bed of equal length has to be made. If the flower bed in each of the fields is $3 \ m$ wide,then what is the maximum length of the flower bed in each of the fields? (in $m$)

The largest natural number which exactly divides the product of any four consecutive natural numbers is

Find the smallest whole number which is exactly divisible by $6, 8, 15, 18$ and $24$.

The greatest number that divides $411, 684,$ and $821$ and leaves $3, 4,$ and $5$ as remainders,respectively,is

Seema,Meena,and Reena start jogging around a circular stadium and complete one round in $54 \text{ seconds}$,$42 \text{ seconds}$,and $63 \text{ seconds}$ respectively. Approximately after how many minutes will they meet again at the starting point?