Question

(i)In 256 sets of 12 tosses of a coin, in how many cases one can expect 8 head and 4 tails?

(ii)A bag contains 7 white, 6 red and 5 black balls. Two balls are drawn at random. Find the probability that they will both be white.

(iii)Find the probability of drawing an ace or a spade or both from a deck of cards.

Answer 1

i)P(getting 8 heads in 12 toss)=p= =0.12085

hence out of 256 sets ; expected number of  cases one can expect 8 head and 4 tails=np=256*0.12085=30.9375

ii)

probability that they will both be white=P(first white)*P(second white|first white)=(7/18)*(6/17)=0.1373\

iii)

as total ace =4 and total spade cards =13 while 1 card is ace as well space

hence total 4+13-1=16 cards which are either ace or spade

probability of drawing an ace or a spade or both from a deck of cards=16/52=4/13