Official Solution:There are two teams in a chess tournament, Team India and Team USA, and no player represents both teams. Each player from Team India plays with each player from Team USA exactly once, resulting in a total of 60 matches between the teams. How many players are on Team USA? Assuming there are \(x\) players in Team India and \(y\) players in Team USA, a total of 60 matches implies that \(xy = 60\). Hence, we can have the following possible pairs of \((x, y)\):
(2, 30)
(3, 20)
(4, 15)
(5, 12)
(6, 10)
(10, 6)
(12, 5)
(15, 4)
(20, 3)
(30, 2)
(1) For every 3 players from Team India, there are 5 players from Team USA.
This implies that \(x : y = 3 : 5\). From the possible pairs, only \(x = 6\) and \(y = 10\) satisfy this. Therefore, there are 10 players on Team USA. Sufficient.
(2) There are a total of 16 players on both teams combined.
This implies that \(x + y = 16\). From the possible pairs, both \(x = 6\), \(y = 10\) and \(x = 10\), \(y = 6\) satisfy this. Therefore, there can be 6 or 10 players on Team USA. Not sufficient.
Answer: A