Given $i=\{A,B,C\}$
$A: n=3, P(\text{Success})=1/8$
$B: n=5, P(\text{Success})=1/4$
$C: n=2, P(\text{Success})=1/2$
And assuming that trials are independent for all $n$, I am trying to find the Variance of the number of times a target will be hit.
To me this seems like a Bernoulli Random Variable, so I assume you can calculate the Variance of hits for all trials as the sum of all variances for each player.
That gives: $$\text{Var}(\text{Hit})=3(1/8)(7/8)+5(1/4)(3/4)+2(1/2)(1/2).$$
Can I calculate the variance of the number of times the target will be hit in this way?
$\newcommand{\Var}{\operatorname{Var}}$ I would like to flesh out some details to provide possible guidance.
It seems like the scenario is something like there are three archers, $A,B,C$, and each has accuracy $1/8,1/4,$ and $1/2$ respectively. Find the expectation and varaince of the number of successful shots.
Let $X_i$ for $i = A,B,C$ denote the number of successful shots. Then, yes, each individual shot is a Bernoulli trial with success $1/8,1/4$ and $1/2$ for each archer.
However, notice that $X_A$ is the number of successes in $n = 3$ independent trials with chance $1/8$ of success. Hence $$X_A\sim\text{Binomial}(3, 1/8).$$
Similarly, $$X_B\sim\text{Bin}(5,1/4)$$ and $$X_C\sim\text{Bin}(2, 1/2).$$
If we call $X = X_A+X_B+X_C$ the number of total successful shots, then $$E[X] =E[X_A]+E[X_B]+E[X_C] = 3\cdot\frac{1}{8}+5\cdot\frac{1}{4}+2\cdot\frac{1}{2} = \frac{21}{8},$$ and by independence $$\Var(X) = \Var(X_A)+\Var(X_B)+\Var(X_C) = 3\cdot\frac{1}{8}\cdot\frac{7}{8}+5\cdot\frac{1}{4}\cdot\frac{3}{4}+2\cdot\frac{1}{2}\cdot\frac{1}{2} = \frac{113}{64}.$$
Notice that $X$ is does not follow a binomial distribution.