176/2^10 = 0.171875.
Let X=no. of probability he guesses right.
Now if he has to pass the quiz with more than 70% grade then, he has to guess more than 7 probability i.e, X=7 or 8 or 9 or 10.
The probability of guessing any prob. right is (1/2).similarly, the Probability of guessing any probability wrong is (1/2).
Probability of guessing exactly 7 questions right =(10C7)((1/2)^7)*(1/2)^3;
(where (1/2)^7 corresponds to the probability of 7 right and (1/2)^3 corresponds to the probability of guessing 3 wrong).
similarly,
Probability of guessing exactly 8 questions right =(10C8)((1/2)^8)*(1/2)^2;
Probability of guessing exactly 9 questions right =(10C9)((1/2)^9)*(1/2)^1;
Probability of guessing exactly 10 questions right =(10C10)((1/2)^10)*(1/2)^0;
So the total probability is the sum of all the above probabilities =
176/2^10 = 0.171875.
For more information on probability click on the link below:
https://brainly.com/question/24756209
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