Statistics: Calculate expected value for test questions, spinning the pointer

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1. In a multiple-choice test, each question has five options. Students will get 10 points for each correct answer; lose 2 points for each incorrect answer; and receive no points for unanswered questions. A student does not know the correct answer for one question. Is it to her advantage or disadvantage to guess an answer? Show your calculations for expected value.

2. A person spins the pointer and is awarded the amount indicated by the pointer.
It costs $6 to play the game.

Determine:
The expectation of a person who plays the game.
The fair price to play the game.

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