The LCM of two numbers is 20 times of their HCF and (LCM

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The LCM of two numbers is 20 times of their HCF and (LCM + HCF) = 2520. If one number is 480, what will be the triple of another number?

1. 1200
2. 1500
3. 2100
4. 1800
5. None of the above

Correct Option: D

Let HCF = N
According to the question, LCM = 20N
Given that, HCF + LCM = 2520
⇒ N + 20N = 2520
⇒ N = 2520 / 21 = 120
Now, LCM = 20N = 20 x 120 = 2400

We know that,
1st number x 2nd number = HCF x LCM
⇒ 2nd number = (LCM x HCF) / (1st number)
= (120 x 2400) / 480 = 600
∴ Required answer = 600 x 3 = 1800