A is a prime number. It is given that LCM (A, 30) = 210. What is the value of A?
7
Prime factorisation: 30 = 2 × 3 × 5 and 210 = 2 × 3 × 5 × 7.
LCM(A, 30) = 210 means A must supply the extra prime factor 7 that 30 lacks.
As A is prime, A = 7, and LCM(7, 30) = 210 checks out.
Hence, the answer is 7.
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Important Questions from LCM and HCF
The HCF and LCM of two numbers are 12 and 72, respectively. If the ratio of the two numbers is 2 ∶ 3, then the larger of the two numbers is:
Find the greatest number that will divide 43, 91 and 183 so as to leave the same remainder in each case.
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What is the least number which when divided by 12,20 and 24 leaves in each case a remainder of 8?
Which of the following is a pair of co-primes?
