Q10 of 123 Page 3

Let * be a binary operation on N given by a*b = LCM(a,b) for all a,b∈N. Find 5*7.

Given that * is an operation that is valid for the natural numbers ‘N’ and is defined by a*b = LCM(a,b).


We need to find the value of 5*7.


According to the Problem, Binary operation is assumed to be true for the values of a and b to be natural.


⇒ 5*7 = LCM(5,7)


We know that LCM of two prime numbers is the product of that given two prime numbers.


⇒ 5*7 = 5×7


⇒ 5*7 = 35


∴ The value of 5*7 is 35.


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