2. Can two numbers have 18 as their HCF and 380 as their LCM? Give rea...
Its not possible for any number to have "18" as “HCF” and "380" as their “LCM” respectively.
To Determine:
Whether any two numbers have their "HCF" as "18" and their "LCM" as "380".
Solution:
HCF tends to be the factor of given LCM
So here HCF = 18 and LCM = 380
Let’s check whether 18 is a factor of the given HCF "380"
380/18 = 21.111
Hence two numbers can’t have “18” as their "HCF" and “380” as their "LCM".
2. Can two numbers have 18 as their HCF and 380 as their LCM? Give rea...
Solution:
Given HCF (Highest Common Factor) = 18 and LCM (Least Common Multiple) = 380 for two numbers.
We need to check if two numbers exist with these given HCF and LCM.
Let the two numbers be a and b.
Prime Factors of 380 = 2^2 × 5 × 19
Prime Factors of 18 = 2 × 3^2
LCM of two numbers = Product of two numbers/HCF of two numbers
Therefore, ab/18 = 380
ab = 18 × 380
ab = 2^2 × 3^2 × 5 × 19 × 2^3 × 5
ab = 2^5 × 3^2 × 5^2 × 19
Now, the HCF of two numbers can only have common factors of the prime factorization of 18.
So, the common factors between a and b are 2 and 3.
Therefore, the two numbers can be written as:
a = 2 × 3 × x
b = 2 × 3 × y
where x and y are co-prime.
ab = 2^5 × 3^2 × 5^2 × 19
(2 × 3 × x) × (2 × 3 × y) = 2^5 × 3^2 × 5^2 × 19
xy = 2^3 × 5 × 19
As x and y are co-prime, they can either be 1 and 1520 or 2 and 760.
Therefore, the two numbers can be:
a = 2 × 3 × 1 = 6
b = 2 × 3 × 1520 = 9120
OR
a = 2 × 3 × 2 = 12
b = 2 × 3 × 760 = 4560
Thus, two numbers can have 18 as their HCF and 380 as their LCM.