Two men ask you to guess their ages based on the following clues:
the sum of their ages is 76. one of the men is 16 years older than twice the age of the other.
need two equations and solve!
it already provided one equation. which is:
x + y = 76

Lets make x equal the the age of the younger man and y equal the age of the older man.
You are given x+y=76 and you can make the equation 2x+16=y since we are told that the older one is 16 more than twice the age of the younger one.  Since we have 2 equations and with the same variable and one has y already written in terms of x (y=2x+16) i will use substitution and make the given equaton all in terms of x.
x+(2x+16)=76 (solve this for x)
3x+16=76
3x=60
x=20
Then you can solve for y using the equation the equaion x+y=76 since we now know x=20.
20+y=76
y=56

Second equation is y=2x+16 (can also be written as y-2x=16)
x=20
y=56

I hope this helps.  If anything is unclear or you just want further explanation please let me know in the comments.

C. 40,320 just did the math right now