The Highest Common Factor of two numbers is (2/5)th of their Least Common…
2021
The Highest Common Factor of two numbers is (2/5)th of their Least Common Multiple. If the product of two numbers is 1690, then what is their Highest Common Factor?
- A.
35
- B.
65
- C.
26
- D.
53
Attempted by 45 students.
Show answer & explanation
Correct answer: C
To find the Highest Common Factor (HCF) of the two numbers, we can use the fundamental relationship between HCF, Least Common Multiple (LCM), and the product of two numbers.
Step-by-Step Calculation
Define the variables and relationships:
Let the HCF be h and the LCM be l.
The problem states that the HCF is (2/5) of the LCM: h = (2/5) * l
This also means: l = (5/2) * h = 2.5 * h
We know the fundamental property: Product of two numbers = HCF * LCM
Given: Product = 1,690
Set up the equation:
Substituting the relationship into the product property:
h * (2.5 * h) = 1,690
2.5 * h² = 1,690
Solve for h (HCF):
h² = 1,690 / 2.5
h² = 676
h = √676
h = 26