Answer:
11/16
Explanation:
P(THHH)=4!3!∗(12)4=416P
(THHH)=4!3!∗(12)4=416, we are multiplying by 4!/3! since THHH scenario can occur in number of ways: THHH, HTHH , HHTH, or HHHT (notice that 4!/3! basically gives number of arrangements of 4 letters THHH out of which 3 H's are identcal).
P(T≥2)=1−(1/16+4/16)=11/16