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 Question from Gita, a parent: Ok, we really need help for a homework problem due on Monday morning I've been trying for 2 hours and can't figure it out---if I can't I'm not sure how my son can....We've been given a puzzle with the following rules: --The sum of each side must equal 15 --We can only use the numbers 1,2,3,4,5,6,7, 8 --A number can be used only once (Hint: Think of all combinations of 3 numbers = 15) --The puzzle looks like this: _____ _______ ______ _____               ______ _____ _______ ______

Hi Gita,

If you look at ways of selecting 3 numbers from 1, 2, 3, 4, 5, 6, 7 and 8 you will find that there is only one combination that and contains the number 1 and sums to 15. 1 + 6 + 8 = 15. Thus the combination 1, 6, 8 must be in the solution somewhere since it is the only way to include the number 1.

Since no other 3 number combination contains the 1 and sums to 15, 1 can't be in a corner. Thus you can start with

 6 1 8

Now for the sides you need two, 3 number combination that sum to 15, one that contains a 6 and the other contains an 8. Since the sides don't meet these two 3 number combinations can't have any numbers in common.

Can you complete if from here?

If you need more help write back,
Penny

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