Three numbers are in the ratio $3: 4: 5$ and their $LCM$ is $2400$. Their $HCF$ is

If the students of $9^{th}$ class are arranged in rows of $6, 8, 12$ or $16$,no student is left behind. The possible number of students in the class is

Philip, Tom, and Brad start jogging around a circular field and complete a single round in $18\, \text{seconds}$, $22\, \text{seconds}$, and $30\, \text{seconds}$, respectively. In how much time will they meet again at the starting point?

Find the greatest number which will divide $25, 73$ and $97$ so as to leave the same remainder in each case.

$A$ wholesale tea dealer has $408$ kilograms,$468$ kilograms,and $516$ kilograms of three different qualities of tea. He wants to pack all of it into boxes of equal size without mixing the different qualities. Find the capacity of the largest possible box.

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.