Question

Make an organized list which shows all possible outcomes when four fair coins are flipped.Each coin lands facing either heads up (H) or tails up (T).What is the probability that at least three coins land facing tails up? Give the probability as a percent, rounded to the nearest whole number.P(at least three tails) =

Answer 1

Sample Space

= { HHHH , HHHT, HTHH , HHTT , HHTH , HTHT , HTTH , HTTT , TTTT , TTTH ,THTT, TTHH ,TTHT ,THTH, THHT ,THHH}

n(S) = 16

at least three coins land facing tails up T= { HTTT , TTTT , TTTH ,THTT, TTHT }

n(T)=5

P(at least three tails) = n(T)/n(S) = 5/16

∴ the percentage is = 31.25%

Explanation: