AP State Syllabus AP Board 9th Class Maths Solutions Chapter 14 Probability InText Questions and Answers.

## AP State Syllabus 9th Class Maths Solutions 14th Lesson Probability InText Questions

**Do This**

Question 1.

Observe the table given in the previous page (Textbook Page No. 293) and give some other example for each term. [Page No. 294]

Solution:

Certain : Independence day on 15th Aug.

More likely : When a die is thrown, the chance of getting a number less than or equal to 5. Equally likely : When a coin is tossed, getting a head.

Less likely : When a die is thrown, the chance of getting neither prime nor composite. Impossible : When a die is thrown, getting a negative number.

Question 2.

Classify the following statements into the categories less likely, equally . likely, more likely. [Page No. 294]

a) Rolling a die and getting a number 5 on the top face.

b) Getting a cold wave in your village in the month of November.

c) India winning the next soccer (foot ball) world cup.

d) Getting a tail or head when a coin is tossed.

e) You buy a lottery ticket and win the jackpot.

Solution:

a) less likely

b) more likely

c) less likely

d) equally likely

e) more likely

**Try These**

Question 1.

If you try to start a scooter, what are the possible outcomes ? [Page No. 295]

Solution:

[Starts], [Doesn’t start]

Question 2.

When you roll a die, what are the six possible outcomes ? [Page No. 295]

Solution:

1, 2, 3, 4, 5 and 6.

Question 3.

When you spin the wheel shown, what are the possible outcomes ? (Outcomes here means the possible sector where the pointer stops) [Page No.295]

Solution:

A, B and C.

Question 4.

You have ajar with five identical balls of different colours. [White, Red, Blue, Grey and Yellow] and you have to pick up (draw) a ball without looking at it. List the possible outcomes you get. [Page No. 295]

Solution:

White ball, Red ball, Blue ball. Grey ball and Yellow ball.

**Think, Discuss and Write**

In rolling a die [Page No. 295]

Question

Does the first player have a greater chance of getting a six on the top face ?

Solution:

No. The chance of getting 6 on the top face is independent of the turn of the player.

Question

Would the player who played after him have a lesser chance of getting a six on the top face?

Solution:

No.

Question

Suppose the second player got a six on the top face. Does it mean that the third player would not have a chance of getting a six on the top face ?

Solution:

No. The third player may or may not get six on the top face. It is indepen¬dent of 2nd player’s outcome.

**Do This**

Question

Toss a coin for number of times as shown in the table. And record your findings in the table [Page No. 296]

Solution:

Question

What hapens if you increase the num- her of tosses more and more.

Solution:

If you increase the number of tosses more and more they are equally likely chances to get a head or a tail.

Note : This could also be done by the students with a die, roll it for large number of times and observe!

**Do This**

If three coins are tossed simulta¬neously : [Page No. 299]

a) Write all possible outcomes.

Solution:

HHH, HHT, HTH, THH, HTT, THT, TTH, TTT, total 8 outcomes.

b) Number of possible outcomes.

Solution:

8

c) Find the probability of getting at least one head, (getting one or more than one head)

Solution:

P = \(\frac{\text { favourable outcomes }}{\text { total outcomes }}=\frac{7}{8}\)

d) Find the probability of getting at most two heads, (getting two or less than two heads)

Solution:

P = \(\frac{\text { favourable outcomes }}{\text { total outcomes }}=\frac{7}{8}\)

e) Find the probability of getting no tails.

Solution:

P = \(\frac{\text { favourable outcomes }}{\text { total outcomes }}=\frac{1}{8}\)

**Try This**

Find the probability of each event when a die is rolled once. [Page No. 300]

**Try These**

From the figure given below [Page No. 306]

Question 1.

Find the probability of the dart hit¬ting the board in the circular region B. (i.e., ring B)

Solution:

Area of innermost ‘C’ circle = πr^{2}

= π x 1^{2} = π sq. units.

Area of the middle ‘B’ circle

= π (2^{2} – 1^{2}) = π (4 – 1) = 3π sq.units.

Area of the outermost ’A’ circle

= π (3^{2} – 2^{2}) = π (9 – 4) = 5π sq.units.

Probability of hitting the circle B

Question 2.

Without calculating, write the percent¬age of probability of the dart hitting the board in circular region ‘C’ (Le., ring C).

Solution:

\(\frac{1}{9}\) x 100% = 11\(\frac{1}{9}\)