Pausing before you answer a hard question doesn’t look dumb. It looks like thinking.

Silence feels far longer from the inside, which is why people fill it with the first available sentence and then spend the rest of the conversation defending that sentence. From outside, a pause reads as somebody taking the question seriously. An instant answer signals that you had one ready, which is not the same as having a good one. Nobody has ever been marked down for a two-second gap.

In your next interview or class, count to two before you start speaking. Use the time to work out what is actually being asked. If you need longer than that, say you are thinking.