Given any two relatively prime numbers what is the greatest

Given any two relatively prime numbers, what is the greatest counting number that cannot be expressed using these numbers either singly, repeatedly, in addition, or in combination? (Relatively prime numbers have no common factors. They\'re not necessarily prime.)

Solution

The greatest counting number that cannot be expressed using these numbers either singly, repeatedly, in addition, or in combination is the number obtained by multiplying those two relatively prime numbers . For example

28 and 45 are relatively prime so the number is 28*45=1260.