- A7:07:12 a.m.
- B7:06:00 a.m.
- C7:07:36 a.m.
- D7:08:24 a.m.
To find when they will change simultaneously again, calculate the Least Common Multiple (LCM) of 48, 72, and 108. LCM(48, 72, 108) = 432 seconds. Convert 432 seconds to minutes and seconds: 432 / 60 = 7 minutes and 12 seconds. So, they will change simultaneously at 7:07:12 a.m.
More Questions on Playing With Numbers
The least number that is divisible by all numbers from 1 to 5 (inclusive) is:
→ 2Which digit should be at the unit's place of a number if it is divisible by both 2 and 5?
→ 3Two ropes of length 15m and 20m are to be cut into small pieces of equal length. What is the greatest possible length of each piece?
→ 4If the HCF of two numbers is 8, which of the following cannot be their LCM?
→ 5Which of the following is true about factors?
→ 6What is the sum of the first five prime numbers?
→ 7A number that has more than two factors is called a:
→ 8If the number 1A3 is divisible by 3, what are the possible values of A?
→ 9How many multiples of 7 are there between 20 and 50?
→ 10Which of the following numbers is an even composite number?
→ 11The LCM of two numbers is 60 and their HCF is 5. If one of the numbers is 20, what is the other number?
→ 12What is the smallest number that must be added to 3456 to make it divisible by 10?
→ 13The HCF of 45 and 75 is:
→ 14If a number is divisible by 11, which of these is correct about the number?
→ 15Which of the following is not a factor of 120?
→ 16What is the difference between the smallest 3-digit number and the largest 2-digit number?
→ 17A shopkeeper wants to arrange 120 apples and 180 oranges into identical boxes such that each box contains only one type of fruit and the greatest possible number of fruits. How many fruits will be in each box?
→ 18Which of the following numbers is divisible by 9 but NOT by 6?
→ 19What is the sum of the HCF and LCM of 12 and 18?
→ 20How many factors does a prime number have?
→ 21What is the smallest 3-digit number formed using digits 1, 2, 3 exactly once that is divisible by 3?
→ 22If an odd number is multiplied by an odd number, the product is always:
→ 23Which number is both a factor of 24 and a multiple of 4?
→ 24Two pieces of string are 42 cm and 63 cm long. What is the greatest possible length of string that can be used to cut both pieces into equal smaller pieces without any wastage?
→ 25What is the smallest number that leaves a remainder of 1 when divided by 3, 4, and 5?
→ 26Which of these is NOT a multiple of 12?
→ 27Find the LCM of 7 and 11.
→ 28A number is divisible by 10 if its last digit is:
→ 29Which of the following numbers has exactly 3 factors?
→ 30What is the greatest 4-digit number that is exactly divisible by 3 and 5?
→ 31If a number is divisible by 8, it must also be divisible by:
→ 32How many even prime numbers exist?
→ 33The sum of two consecutive even numbers is 54. What is the smaller number?
→ 34Which of the following is divisible by both 3 and 5?
→ 35What is the HCF of 17 and 19?
→ 36I am a number between 70 and 80. I am a multiple of both 3 and 5. What number am I?
→ 37What is the least number of mangoes that can be put into baskets containing 9, 12, or 15 mangoes each, without any remaining?
→ 38Which of the following is a composite number?
→ 39What is the LCM of 16, 24, and 36?
→ 40What is the HCF of 105, 120, and 150?
→ 41If a number is divisible by both 2 and 3, it is also divisible by:
→ 42Which of the following is the correct prime factorization of 144?
→ 43The sum of three consecutive odd numbers is 93. What is the largest of these numbers?
→ 44Which of the following is a pair of twin primes?
→ 45What is the HCF of two consecutive even numbers?
→ 46Which of the following is the smallest number that is a multiple of 6, 8, and 10?
→ 47A number is divisible by 9 if the sum of its digits is divisible by 9. Which digit should replace * in 24*71 to make it divisible by 9?
→ 48If two numbers are co-prime, what is their HCF and LCM?
→ 49If the prime factorization of a number is 2³ * 3² * 5¹, how many factors does this number have?
→ 50What is the greatest 3-digit number that is exactly divisible by 8, 12, and 15?
→ 51What is the smallest composite number?
→ 52Which of the following numbers is divisible by 5 but not by 10?
→ 53What is the least number of square tiles required to pave the floor of a room 180 cm long and 150 cm wide?
→ 54Find the greatest number that will divide 66 and 110 leaving remainders 6 and 2 respectively.
→ 55Consider the number 15. Which of the following statements is true?
→ 56Which of the following numbers is divisible by 4 but NOT by 8?
→ 57Which of the following pairs of numbers are co-prime?
→ 58Which of the following statements about even and odd numbers is always true?
→ 59What is the greatest number that divides 45 and 60, leaving a remainder of 0 in each case?
→ 60What is the smallest number which when divided by 12, 15, and 20 leaves a remainder of 5 in each case?
→ 61How many factors does the number 36 have?
→ 62Which of the following conditions is required for a number to be divisible by 6?
→ 63What is the sum of the prime factors of 210?
→ 64Three different containers contain 12 litres, 18 litres, and 30 litres of milk respectively. What is the maximum capacity of a container that can measure the milk of all the three containers an exact number of times?
→ 65What is the smallest digit that should replace * in the number 83*64 to make it divisible by 11?
→ 66How many prime numbers are there between 50 and 70?
→ 67The product of two numbers is 1800. If their HCF is 15, what is their LCM?
→ 68If the number 75P8 is divisible by 4, which of the following could be the digit P?
→ 69What is the smallest 4-digit number that is exactly divisible by 12, 18, and 24?
→ 70Which of the following statements is always true about prime numbers?
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