Each question has four choices, then the probability to guess a correct answer is 
and the probability to select incorrect choice is 
.
You have a 5-question multiple-choice test, then n=5. The <span>probability that you will guess exactly three out of five questions correctly is </span>
<span /><span>
</span><span>
</span>
.
<span />
You have a 5-question multiple-choice test, then n=5. The <span>probability that you will guess exactly three out of five questions correctly is </span>
<span /><span>
</span><span>
<span />