Question

Four positive whole numbers add up to 39. One of the numbers is a Multiple of 7. The other three numbers are equal. Work out the result when the four numbers are mutliplied.

Answer 1

4 positive whole numbers add up to 39. That means there are 4 factors. One is a multiple of 7. (7,14,21,28,35) The other 3 are equal. Let X equal the multiple of 7, and let Y equal the numbers that are equal.
39=x+3y
Now, we have to fill in the possible multiples of 7.

39=7+3y
39-7=7-7+3y
32=3y
32/3=3y/3
10&2/3=y
When we use 7, the 3 numbers are not equal whole numbers. Let's try the next multiple.
39=14+3y
39-14=14-14+3y
25/3=3y/3
5=y
Yes, that is a whole positive number. It's correct.

We have to plug in the other multiples just to check, but I'll leave out the work.

39=21+3y
6=y
Yes, that is a possible answer.

39=28+3y
3&2/3=y The 3 numbers are not whole numbers.

39=35+3y
1&1/3=y The 3 numbers are not whole numbers.


In conclusion, the TWO possible answers are 39=14+3(5) and 39=21+3(6). If we multiply all four numbers for the first one then it equals 1750, and the second one equals 4536. Not sure what exactly your looking for, but I answered the best I could! Hope this helped. :)