MickeyD has a lottery scratch card that claims "1 in 4 wins". Assuming that there are many scratch cards so that the chance that each card wins is 1/4 independently.

What is the approximate probability that when you scratch 4 lottery cards, you will win a prize?

70%
80%
90%
100%

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The probability of not winning a prize, when scratching 4 cards:

$(1-0.25)^4 = 0.75^4 = 0.31640625$

Hence, the probability of winning at least one prize, when scratching 4 cards:

$1- (1-0.25)^4 = 1- 0.75^4 = 1 - 0.31640625 =$

$= 0.68359375 = \boxed { 70 \% } \text { ( 1 s. f. ) }$