Sunday, October 12, 2014

2014/091) The LCM and GCD of two composite numbers total 111. What are the numbers?

Let the gcd be t
the 2 numbers are at and bt with a < b where a and b are coprimes or a  =1

Therefore, the LCM = abt

 so abt + t = 111 or 111 = t(1+ab) = 3 * 37

then we have following cases
t = 1 , ab = 110 then a = 1, b= 110 giving 2 numbers 1 and 110
                                 a = 2, b= 55 giving 2 numbers 2 and 55
                         or a = 5 , b = 22 giving 2 numbers 5 and 22
                         or a = 10, b = 11 giving 2 numbers 10 and 11
t=3, ab = 36 then a = 1, b= 36 giving 2 numbers 3 and 108
                             a = 4, b= 9 giving 2 numbers 12 and 27
t = 37, ab =2 then a = 1, b=2 giving 37 and 74

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