Question of Solved Question

Probability of Class 9

Question

An insurance company selected 2000 drivers at random in a particular city to find a relationship between age and accidents. The data obtained are given in the following table:

Age group of drivers (in years)

Number of accidents in one year

0

1

2

3

more than 3

18 – 29

30 – 50

Above 50

440

505

360

160

125

45

110

60

35

61

22

15

35

18

9

Find the probability of the following events for a driver selected at random from the city:

(i) being 18 – 29 years of age and having exactly 3 accidents in one year.

(ii) being 30 – 50 years of age and having one or more accidents in a year. (iii) having no accident in one year.

Frequently Asked Questions

Simplify the following expressions

(√(5) + √(2))2

 

Solution:

Explanation:

 

Simplify

Which of the following rational numbers lies between 0 and - 1

A: 0

B: - 1

C: -1/4

D: 1/4

 

Solution:

Explanation:

0 and 1 cannot be found between 0 and 1.

In addition,0= o/4  and -1= -4/4

We can see that -1/4 is halfway between 0 and -1.

Final Answer:

Hence, the correct option is (c) -1/4

 

Prove that the diagonals of a parallelogram bisect each other

Solution:

Explanation:

We must show that the diagonals of the parallelogram ABCD cross each other.

OA = OC & OB = OD, in other words.

Now AD = BC [opposite sides are equal] in ΔAOD and ΔBOC.

[alternative interior angle] ∠ADO = ∠CBO in ΔAOD and ΔBOC.

Similarly, ∠AOD = ∠BOC by ΔDAO = ΔBCO (ASA rule)

As a result, OA = OC and OB = OB [according to CPCT].

according to CPC

Final Answer:

Hence, it is prove that the diagonals of a parallelogram bisect each other.

 

What is total surface area of sphere

Solution:

Explanation:

  • The radius of the sphere affects the formula for calculating the sphere's surface area. 
  • If the sphere's radius is r and the sphere's surface area is S.
  • The sphere's surface area is therefore stated as Surface Area of Sphere 4πr2, where ‘r’ is the sphere's radius.
  • The surface area of a sphere is expressed in terms of diameter as S=4π(d/2)2, where d is the sphere's diameter.

Final Answer:

Thus, total surface area of sphere is =4πr2.

 

Fill in the blanks If two adjacent angles are supplementary

 they form a __________.

Solution:

Explanation:

  • If the non-common sides of two angles form a straight line, they are called linear pair angles. 
  • The sum of the angles of two linear pairs is  degrees.
  • If the total of two angles is  degrees, they are called supplementary angles.

Final Answer:

A linear pair is formed.

 

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