Answer
Number of ways to select one out of three choice to answer all questions= $5_{{C}{_{1}}}\times3_{{C}{_{1}}}$ = 15
Work Step by Step
Number of questions in a test = 5
Each question has answer choices = 3
Number of ways to select one out of three choice to answer all questions= $5_{{C}{_{1}}}\times3_{{C}{_{1}}}$ = 5 $\times$ 3 = 15