maths
posted by ?????? on .
at a fairground, the table shows the prbability of winning an amount on a spinner. what is the minimum amount that can be charged to make profit from the game?
amount 5p 10p 20p 50p
prbability 0.5 0.25 0.15 0.1
can you show how you worked it out? thanks

expected value
= .5(5) + .25(10) + .15(20) + .1(50)
= .25 + 2.5 + 3 + 5
= 10.75 p
but I assume p stands for pence and thus we would have to charge 11 p to profit from the game
(at 10 p we would be losing)