Don't really need to post the options to know what the expression(s) should look like.
"Sum of" tells you its addition and because it's addition the order of the two terms (the 3 and the N) don't matter.
Your correct expressions are:
3 + n
or
n + 3
The answer is 24, hopes this helps!
An arrowhead or point is the usually sharpened and hardened tip of an arrow, which contributes a majority of the projectile mass and is responsible for impacting and penetrating a target, as well as to fulfill some special purposes such as signaling.
1/2 is the probability the coin would land heads up both times.