Consider a 10-question test in which each question can be answered either correctly or incorrectly.
How many different ways are there to answer the question so that at least eight are correct?
The answer is 56..how??

Question

Consider a 10-question test in which each question can be answered either correctly or incorrectly. 
How many different ways are there to answer the question so that at least eight are correct?
The answer is 56..how??

owlfred · Answer

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lindsay · Answer

thanks

lindsay · Answer

I know you are supposed to use combinations to solve this, but I am stuck, please help

anonymous · Answer

as the question says atleast 8 it implies either 8 or 9 or 10 questions are correct.......
=> 10c8 ( for 8 correct) + 10c9(for 9 ) + 10c10 (for 10) = 45 + 10+1=56