Answer:
We want to solve:
___ + ___ + ____ = 30
using the numbers:
1, 3, 5, 7, 9, 11, 13, 15.
Now, 30 is an even number.
And the given numbers are all odd.
A random even number is written as:
2*n (where n is an integer)
A random odd number is written as:
2*k + 1 (where k is an integer)
If we add 3 odd numbers, we get:
(2*k + 1) + (2*c + 1) + (2*j + 1) = 2*(k + c + j) + 3
= 2*(k + c + j + 1) + 1
(k + c + j + 1) is an integer, then we can write this as p
then the sum of 3 odd numbers can be written as:
2*p + 1
This means that the sum of 3 odd numers is always an odd number.
Then we can not find 3 odd numbers such that their sum is equal to 30.
if instead, we could use 4 numbers, like:
___ + ___ + ___ + ___ = 30
Then we could select:
15, 1, 5 and 9.
because:
15 + 1 + 5 + 9 = 15 + (1 + 5) + 9 = 15 + 6 + 9 = 15 + (6 + 9) = 15 + 15 = 30