Question 274951: A, B and C are whole and positive numbers.
A+B+C=38 and A*B*C=630. What are the numbers?
How do I find that out with three variables and only two equations?
Thanks so much!
Guðrún
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website! Because we're only looking for positive integer solutions, this set of solutions will be finite even though we're missing a third equation. To find these solutions, simply list all of the factors of 630 and see which set of 3 factors add up to 38. For example, 630=2*5*63 which means that 2+5+63=70.
It turns out that there are only 6 sets of solutions and they are
A = 2, B = 15, C = 21
A = 2, B = 21, C = 15
A = 15, B = 2, C = 21
A = 15, B = 21, C = 2
A = 21, B = 2, C = 15
A = 21, B = 15, C = 2
For example, when A = 2, B = 15, C = 21, then 2*15*21=630 and 2+15+21=38
Basically, there are 3 unique numbers here (they're just being rearranged) and the numbers are 2, 15, and 21.
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