A can solve 90% of the problems given in a book and B solve 70%. What is the probability that at least one of them will solve a problem selected at random from the book?

• prob of A to solve =.9
  prob of A to solve =.7
  prob of both to solve =.9*.7
  here we find atleast one ie p(a or b)
  p(a or b)=p(a)+p(b)-p(a and b)
  =>.9+.7-.63
  =>.97
  ans is .97
  
• 11 years agoHelpfull: Yes(25) No(0)
• Prob that atleast one will solve=1-(prob that none will solve)
  Prob that A will not solve=1-0.9=0.1
  Prob that B will not solve=1-0.7=0.3
  So reqd prob=1-(0.3*0.1)
  =1-0.03
  =0.97
• 11 years agoHelpfull: Yes(22) No(0)
• prob A to solve=9/10
  prob A to not solve=1-9/10
  prob B to solve=7/10
  prob B to not solve=1-7/10
  now according to qust atleat one of dem solve d prob=1-1/10*3/10
  so 1-3/100
  =>97/100=.97
• 11 years agoHelpfull: Yes(3) No(0)