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As low as possible (Posted on 2013-04-12)

What is the lowest value of a product of two positive numbers a and b, given that a+b=a*b?

See The Solution Submitted by Ady TZIDON

Rating: 2.0000 (1 votes)

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Analytical solution (spoiler)

| Comment 2 of 6 |

(1) a + b = ab

(2) solving for b, we get b = a/(a-1)

by inspection, b can only be a positive integer if a =2

and

by substitution, b = 2

(3) So the lowest value of ab

= highest value of ab

= only value of ab

= 4

Edited on April 12, 2013, 1:20 pm

Posted by Steve Herman on 2013-04-12 13:13:30

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