Write a letter to your friend congratulating him on his selection as a captain of school cricket team​

'A' writes a letter to his friend 'B' and gives it to his son to post it in a letter box, the reliability of his son being 3/4. The probability that a letter posted will get delivered is 8/9 .At a later date, 'A' hears from 'B' that the letter has not reached him. Find the probability that the son did not post the letter at all .

A debate club consists of 6 girls and 4 boys.A team of 4 members is to be selected from this club including the selection of a captain (from among these 4 members) for the team.If the team has to include at most one boy,then the number of ways of selecting the team is

A debate club consists of 6 girsl nd 4 boys. A team of 4 members is to be selected from this club including the selection of a captain (from among these 4 memers) for the team. If the team has ot include at most one boy. Then the number of ways of selecting the team is (A) 380 (B) 320 (C) 260 (D) 95