A speaks english in 75% of cases and B in 80% of cases. In what percentage of cases are they likely to speak english?  Choose the correct choice from the following:
A) 25%  B) 26%  C) 35%  D) 45%  E) 56%
Let A = Event that A speaks the truth   B = Event that B speaks the truth   Then P(A) = 75/100 = 3/4   P(B) = 80/100 = 4/5   P(A-lie) = 1-3/4 = 1/4   P(B-lie) = 1-4/5 = 1/5   Now   A and B contradict each other =   [A lies and B true] or [B true and B lies]   = P(A).P(B-lie) + P(A-lie).P(B)   [Please note that we are adding at the place of OR]   = (3/5*1/5) + (1/4*4/5) = 7/20   = (7/20 * 100)= 
<gadget id="calculator">(7/20 * 100)</gadget>
<output>35</output>
35%   35%
<result>C</result>
A speaks english in 75% of cases and B in 80% of cases. In what percentage of cases are they likely to speak english?