LCM and HCF
 The product of HCF and LCM of 18 and 15 is

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HCF of 18 and 15
18 = 2 x 3 x 3
15 = 3 x 15 = 3
LCM of 18 and 15 = 2 x 3 x 3 x 5 = 90
∴ Product of HCF and LCM of both numbers = 3 x 90 = 270Correct Option: D
HCF of 18 and 15
18 = 2 x 3 x 3
15 = 3 x 15 = 3
LCM of 18 and 15 = 2 x 3 x 3 x 5 = 90
∴ Product of HCF and LCM of both numbers = 3 x 90 = 270
 The HCF of two numbers is 15 and their LCM is 225. If one of the numbers is 75, then find the another number.

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Product of LCM and HCF = Product of two numbers
Correct Option: D
Let the other number = N
Product of LCM and HCF = Product of two numbers
Then, N x 75 = 15 x 225
∴ N = (15 x 225)/75 = 45
 The HCF of three numbers is 23. If they are in the ratio of 1 : 2 : 3, then find the numbers ?

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Let the numbers are N, 2N and 3N.
Where, N = HCFCorrect Option: B
Let the numbers are N, 2N and 3N.
Where, N = HCF
Given that, N = 23
∴ The numbers are 23, 46 and 69.
 The HCF and LCM of two numbers m and n are respectively 6 and 210. If m + n = 72, then 1/m + 1/n is equal to

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We have, m x n = 6 x 210 = 1260
∴ 1/m + 1/nCorrect Option: D
We have, m x n = 6 x 210 = 1260
∴ 1/m + 1/n = (m + n)/mn = 72/1260 = 4/70 = 2/35
 The ratio of two numbers is 5 : 6 and their LCM is 480, then their HCF is

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Let numbers are 5N and 6N.
Now, HCF of these two numbers is N.
We know that,
LCM x HCF = Product of two numbersCorrect Option: B
Let numbers are 5N and 6N.
Now, HCF of these two numbers is N.
We know that,
LCM x HCF = Product of two numbers
⇒ 480 x N = 5N x 6N
⇒ 480N = 30N^{2}
⇒ N =16