Felicia has a stack of 10 cards. Each card is labeled with a number in the range 1 through 10 and no two cards have the same number. She picks three cards at random from the stack and adds the numbers...

Felicia has a stack of 10 cards. Each card is labeled with a number in the range 1 through 10 and no two cards have the same number. She picks three cards at random from the stack and adds the numbers on the three cards. What is the expected value of the sum?

Extracted text: Felicia has a stack of 10 cards. Each card is labeled with a number in the range 1 through 10 and no two cards have the same number. She picks three cards at random from the stack and adds the numbers on the three cards. What is the expected value of the sum? 15 18 10.5 16.5