Prime Factor Method for L.C.M

Q.

$3$ bells ring at an interval of $4$, $7$ and $14$ $minutes$. All three bell rang at $6am$, when the three balls will the ring together next?

Q.

Three bells toll together at intervals of 30, 36 and 45 minutes respectively. At what time will they toll together again if they toll simultaneously at 8 A.M?

1. 2 P.M

2. 11 A.M

3. 12 A.M

4. 1 P.M

Q.

Find the LCM of $32,64$ and $128$

1. $128$

2. $134$

3. $512$

4. $136$

Q. The LCM of 24, 36 and 108 is:

[1 mark]

1. $216$
2. $108$
3. $512$
4. $432$

Q. The exponent of 2 in the prime factorisation of 64 is:

1. 4
2. 5
3. 6
4. 7

Q.

Anil and Sunil are practicing for sports day. Anil can run for $20$ minutes before taking a break, and Sunil can run for $15$ minutes before taking a break. After how many minutes will they take a break together?

Q. The number $23$ is:
A. a prime number B. a real number
C. an irrational number D. a rational number

1. $A,B,D$ are correct
2. $B,C,D$ are correct
3. $A,B,C$ are correct
4. $A,C,D$ are correct

Q. Write the prime factors of $163800$