Question

the probability of guessing the correct answer to certain is p/12.if probability of not guessing the correct answer to to same question is 3/4.find the value of p.

Answer 1

P[of guessing correct answer]+P[of not guessing correct answer]=1
(p/12)+(3/4)=1
(p/12)+(9/12)=1
(p+9)/12=1
p+9=12
p=12-9
p=3