Consider the following in respect of natural numbers a, b and c: 1. LCM(ab, ac) = a × LCM(b, c) 2. HCF(ab, ac) = a × HCF(b, c) 3. HCF (a, b) < LCM(a, b) 4. HCF(a, b) divides LCM(a, b) Where, a ≠ b ≠ c Which of the above are correct?
Consider the following in respect of natural numbers a, b and c: 1. LCM(ab, ac) = a × LCM(b, c) 2. HCF(ab, ac) = a × HCF(b, c) 3. HCF (a, b) < LCM(a, b) 4. HCF(a, b) divides LCM(a, b) Where, a ≠ b ≠ c Which of the above are correct? Correct Answer 1, 2, 3 and 4
Statement II:
Let the HCF of b and c be t
⇒ b = tp and c = tq where p and q are co-prime numbers
⇒ ab = atp and ac = atq
⇒ HCF(ab, ac) = at
⇒ HCF(ab, ac) = a × HCF (b, c)
⇒ Statement II is correct
LCM (ab, ac) = Product of numbers (ab, ac) /HCF (ab, ac)
⇒ / (at)
⇒ atpq
⇒ a /t
⇒ a × Product of (b, c) /HCF (b, c)
⇒ a × LCM(b, c)
So, Statement I is true
Statement III:
When a = b
⇒HCF (a, a) = a
⇒ LCM (a, a) = a
⇒ LCM (a, a) = HCF (a, a)
⇒ Statement III fails when a = b
But according to question a ≠ b ≠ c
So, Statement III is also correct.
Statement IV:
Let the HCF (a, b) = r
⇒ a = rp and b = rq, where r and q are co prime
LCM = Product of the numbers/HCF
⇒ rp × rq/r = rpq
⇒ LCM = HCF × pq
⇒ HCF divides LCM
⇒ Statement IV is correct
∴ Statement 1, 2 and 4 are true.