Answer: Option C- $29.79
Step by step: First, we're solving for 21% (6%+15%) of 24.62 so,
24.62*.21= 5.1702
Then, you just add that back to the original total
24.62+ 5.1702 = $29.7902 which simplifies to our answer, $29.79
Ps: I took the test and this is the correct answer