Applications of LCM

Q.

Three bells are ringing continuously at intervals of $30,40and45$minutes respectively. At what time will they ring together if they ring simultaneously at $5$A.M.?

Q.

The Binary system is also known as the ___ number system.

1. Base-10
2. Base 2
3. Base 20
4. Base 5

Q.

$11100÷10$ Divide this by binary number

Q.

Convert $37$ to the base $10$ into binary

Q.

During its grand opening weekend, a restaurant gave every eight customer a free drink, every twelfth customer a free snack and every fifteenth customer a free scoop of ice cream.

If $385$customers walked into the restaurant that weekend, how many of them received all three free items $?$

Q. Bell A rings every 5 minutes and bell B rings every 6 minutes. If the two bells rang at 7:00 AM, then at what time will they ring together again? ( 3 marks)

Q. I have 20 oranges. What is the least number of oranges I need to take such that I can divide the oranges into groups of 6 or groups of 9 without leftovers?

1. 15
2. 18
3. 9
4. 12

Q. An octal number 237 is equal to the binary number

1. 010 011 111
2. 010 111 011
3. 011 101 101
4. 011 000 001

Q. Four bells commence tolling together at 1: 00 pm and toll at intervals of 2, 4, 6 and 8 minutes respectively. At what time will the bells toll together again?

1. 1 : 20 pm
2. 1 : 16 pm
3. 1 : 24 pm
4. 1 : 28 pm

Q.

The HCF of 75 and 90 is 15. What is their LCM?

1. 150
2. 300
3. 450
4. 180

Q. Sara goes to dance class once every 6 days, to karate class once every 12 days and to art class once every 18 days. If she attended all the three classes on 1st April then, on which nearest date will she attend all the three classes again?

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