West Bengal Board Solutions for Chapter: Revision of Previous Lessons, Exercise 6: Exercise 6

An educational trip to Gadiyara has been arranged by my school for collecting environment related data. $32$ students of class six, $36$ students of class seven and $28$ students of class eight are going for the trip. Some small school buses have been arranged so that each bus must accommodate equal number of students from the three classes. Let us find the total number of buses required and the number of students in each bus can accommodate.

Find the $HCF$ of $65, 25 \& 55$.

Find the HCF of $48, 80 \& 70$.

Find the HCF of $15 \& 16$.

Find the $HCF$ of $25, 35 \& 60$ by the method of Division.

Find LCM of $12, 18$ and $24$ by finding their prime factors.

Find the least number, which is divisible by $8 \& 9$.

At $5\text{'}\mathrm{o}$ clock in the morning, $3$ cocks crowed together. The first cock crows after every $36 \mathrm{secs}$, the second cock after every $30 \mathrm{secs}$ and the third cock crows after every $48 \mathrm{secs}$. When will the cocks crow together again?