Lecture_04

PROBABILITY

• Finding Probability : Sum based on Fish

: Sum based on tossing 3 coins

= 5 male fish

+ 8 female fish

= 13 fish

Sol.

Number of outcomes favourable to E

= 5

Let ‘ E ’ be the event that a male fish is picked up.

Number of all possible

outcomes of the experiment

= Total number of fish

P(E) =

Number of outcomes favorable to E

Number of all possible outcomes of the experiment

Gopi buys a fish from a shop for his aquarium .The shopkeeper

takes out one fish at random from a tank containing 5 male fish and 8 female fish. What is the probability that the fish taken out is a male fish ?

How many male fishes are there ?

∴ P(E) =

Sol.

Q. A game consists of tossing a one rupee coin 3 times and

nothing its outcome each time. Hanif wins if all the tosses give the same result i.e., three heads or tails, and loses otherwise. Calculate the probability that Hanif will lose the game.

Possible outcomes are

HHH, HTH, THH, TTH, HHT, HTT, THT, TTT

∴ Total no. of possible outcomes = 8

Let A be the event the Hanif will lose the game

Outcomes favourable to A are

HTH, THH, TTH, HHT, HTT, THT

No. of outcomes favourable to A = 6

∴ P (A) =

When a coin is tossed 3 times

We know that when a coin is tossed 3 times possible outcomes are

Hanif will lose game if all tosses do not give same result