Answer:
We want to separate 82 into two parts, let's call the parts A and B.
82 = A + B
And we know that one part is three times the other part, then we can write:
A = 3*B
Then we have a system of equations:
82 = A + B
A = 3*B
We can replace the second into the first equation, and get:
82 = 3*B + B = 4*B
And now we can solve this for B
82 = 4*B
82/4 = 20.5 = B
then:
A = 3*B = 3*20.5 = 61.5
Then the two parts are:
A = 61.5
B = 20.5
and 61.5 + 20.5 = 82
