Question

The PTO is selling raffle tickets to raise money for classroom supplies. A raffle ticket costs $3. There is 1 winning ticket out of the 140 tickets sold. The winner gets a prize worth $84. Round your answers to the nearest cent.

What is the expected value (to you) of one raffle ticket?

Calculate the expected value (to you) if you purchase 8 raffle tickets?

What is the expected value (to the PTO) of one raffle ticket?

If the PTO sells all 140 raffle tickets, how much money can they expect to raise for the classroom supplies?
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Answer 1

A) 0.54

B) 4.32

C) 2.4

D) 336

Explanation:

A)Expected value (you) = (84 × 3) ×
`(1)/(140)` × (0.3)×
`(139)/(140)`

= 0.54

B) Expected value (you) 8 tickets = 0.54 × 8

= 4.32

C) Expected value ( for PTO) = ( 3 - 84) ×
`(1)/(140)` + ( 3 - 0 ) ×
`(139)/(140)`

= 2.4

D) For 140 raffle tickets = 2.4 × 140

= 336