Answer:
15
Explanation:
This is a handshake question.Its logical. If there are six people and each one shakes hands with everyone only once. Then the first person would shake the rest 5 (5 handshakes), the second person would shake only four persons because he had already shook the first (4 handshakes), third person would shake 3 persons (3 handshakes) . and this pattern will continue until the last handshake. The last person would have already had a handshake with everybody so we assume 0 for that case. So we have 5+4+3+2+1+0 = 15 handshake