Answer:
(a) Probability he or she will answer all 10 problems correctly is 0.5
(b) Probability he or she will answer at least 9 problems correctly is 0.95
Step-by-step explanation:
(a) Probability is given by number of possible outcomes ÷ number of total outcomes
Number of possible outcomes = 10 problems
Number of total outcomes = 20 problems
Probability he or she will get all 10 problems correctly = 10 ÷ 20 = 0.5
(b) Probability he or she gets at least 9 problems correctly means he or she either gets 9 or the 10 problems correctly
Probability he or she gets at least 9 problems correctly = (9÷ 20) + (10÷20) = 0.45+0.5 = 0.95
