Probability

[tmutsamwir]

It is believed that 2 genes A and B may play some part in the susceptibility of an individual to a disease .Of 100 patients,17 carry gene A, 33 carry gene B and 67 carry neither. Find the probability that a patient carries only gene A, only gene B or both search from theFree Math world

 

[tkhunny]

You've only four classifications:

A
B
Neither
Both

The last is the only trick.

A + B - Both = 100 - 67

Please explain this formula and let's see your solution.

 

[tmutsamwir]

let x be both genes, then 17-x+x+33-x+67 =100
solving for x =17
therefore 17 patients carry both and 33-17=16 carry B only.and 0 carry A only
therefore P(A)= 0
P(B)=16/100
P(both)=.17