CBSE Class 9 - Mathematics - Probability - Problems and Solutions

Probability

Problems and Solutions (NCERT Exemplar Answers)

Problem 1: Two dice are thrown simultaneously 500 times. Each time the sum of numbers appearing on their top is noted and recorded as given in the following table:

Sum	2	3	4	5	6	7	8	9	10	11	12
Frequency	14	30	42	55	72	75	70	53	46	28	15

If the dice are thrown once more, what is the probability of getting a sum
(i) 3
(ii) more than 10
(iii) less than 5 or equal to 5
(iv) between 8 and 12

Solution: Click here to see the solution.


Problem 2: Here is an extract from a mortality table:

Age(in years)	60	61	62	63	64	65
Number of persons surviving out of sample of one million	16090	11490	8012	5448	3607	2320

(i) Based on this information, what is the probability of a person 'aged 60' of dying within a year?

(ii)What is the probability that a person 'aged 61'will live for 4 years?

Class 9 - Hindi - गीत-अगीत - कविता का सारांश (#CBSEClass9Notes)

गीत-अगीत

रामधारी सिंह ‘दिनकर’ (१९०८-१९७४)

कविता

गीत, अगीत, कौन सुंदर है?

गाकर गीत विरह की तटिनी

वेगवती बहती जाती है,

दिल हलका कर लेने को

उपलों से कुछ कहती जाती है।

तट पर एक गुलाब सोचता,

"देते स्‍वर यदि मुझे विधाता,

अपने पतझर के सपनों का

मैं भी जग को गीत सुनाता।"

गा-गाकर बह रही निर्झरी,

पाटल मूक खड़ा तट पर है।

गीत, अगीत, कौन सुंदर है?

बैठा शुक उस घनी डाल पर

जो खोंते पर छाया देती।

पंख फुला नीचे खोंते में

शुकी बैठ अंडे है सेती।

गाता शुक जब किरण वसंती

छूती अंग पर्ण से छनकर।

किंतु, शुकी के गीत उमड़कर

रह जाते स्‍नेह में सनकर।

Class 11 - Mathematics - Chapter 1– SETS (NCERT Exercise 1.1) (#CBSENotes)

SETS

Class 11 - Mathematics  

NCERT Exercise 1.1

Question 1: Which of the following are sets? Justify your answer.

(i) The collection of all months of a year beginning with the letter J.
(ii) The collection of ten most talented writers of India.
(iii) A team of eleven best-cricket batsmen of the world.
(iv) The collection of all boys in your class.
(v) The collection of all natural numbers less than 100.
(vi) A collection of novels written by the writer Munshi Prem Chand.
(vii) The collection of all even integers.
(viii) The collection of questions in this Chapter.
(ix) A collection of most dangerous animals of the world.


Answer:

(i) Yes
The collection of all months of a year beginning with the letter J is a well-defined collection of objects since one can definitely identify a month that belongs to this collection. Hence, this collection is a set.

(ii) No
The collection of ten most talented writers of India is not a well-defined collection because the criteria for determining a writer’s talent may vary from person to person. Hence, this collection is not a set.

(iii) No
A team of eleven best cricket batsmen of the world is not a well-defined collection because the criteria for determining a batsman’s talent may vary from person to person. Hence, this collection is not a set.

(iv) Yes
The collection of all boys in your class is a well-defined collection because you can definitely identify a boy who belongs to this collection. Hence, this collection is a set.

(v) Yes
The collection of all natural numbers less than 100 is a well-defined collection because one can definitely identify a number that belongs to this collection. Hence, this collection is a set.

(vi) Yes
A collection of novels written by the writer Munshi Prem Chand is a well-defined collection because one can definitely identify a book that belongs to this collection. Hence, this collection is a set.

(vii) Yes
The collection of all even integers is a well-defined collection because one can definitely identify an even integer that belongs to this collection. Hence, this collection is a set.

(viii) Yes
The collection of questions in this chapter is a well-defined collection because one can definitely identify a question that belongs to this chapter. Hence, this collection is a set.

(ix) No
The collection of most dangerous animals of the world is not a well-defined collection because the criteria for determining the generousness of an animal can vary from person to person. Hence, this collection is not a set.

CBSE Class 8 - Science - REACHING THE AGE OF ADOLESCENCE

REACHING THE AGE OF ADOLESCENCE

Q & A Based NCERT Class 8 Science Chapter


Q 1: List the changes occur during adolescent age.

Answer:
CHANGES OCCUR AT ADOLESCENT AGE:
1) INCREASE IN HEIGHT
2) DEVELOPMENT OF HAIR
3) SEXUAL FEELING
4) VOICE CHANGES
5) CHANGE IN BODY SHAPE
6) CHANGE IN BEHAVIOUR AND ATTITUDES
7) ACTIVITY OF SWEAT AND OIL GLANDS


Q 2: What is the function of endocrine system? What is it made up of?

Answer: There are a number of other slower processes that go on in the body, such as growth such processes are primarily controlled by the endocrine system.

The endocrine system consist of a number of ductless glands that secrete hormones.


Q3: What is Adam's apple?

Answer: Adam's apple: The protruding part of the throat is called Adam’s apple. It is the enlarged voice box or larynx which gets enlarged and visible from outside in boys at the onset of puberty. This makes the voice of boys hoarse.


Q 4: Name four body processes that hormones control?

Answer: Growth behavior, development and reproduction are controlled by hormones.

CBSE Open Text Based Assessment (OTBA) for classes IX & XI, 2017 is Available

Open Text Based Assessment (OTBA) 

For classes 

IX & XI  2017

Available Now

OTBA Material for Class 9 and Class 11 for this session (2016-2017) is available at CBSE website. Here are the links to download the pdfs.

Open Text Material for Class IX

Subject- English
Subject- Hindi
Mathematics - English - Hindi
Science - English - Hindi
Social Science - English - Hindi

CBSE Class 7 - Hindi - नीलकंठ - प्रश्न - उत्तर (भाग -१ )

नीलकंठ 

प्रश्न - उत्तर

(भाग -१ )

प्र.1 “जब मैंने वह पिंजड़ा कार में रखा तब मानो वह जाली के चौखटे का चित्र जीवित हो गया।”- इस पंक्ति का अर्थ स्पष्ट करें ।

उत्तर – पिंजड़े की संकीर्णता के कारण मोर-शावकों का हिलना-डुलना भी मुश्किल था। वे उसमें तार के गोल फ्रेम में जुड़ी तस्वीर की तरह स्थिर दिखाई देते थे, परन्तु कार में पिंजड़ा रखे जाने के बाद जब उनकी हलचल शुरू हुई तो ऐसा लगा जैसे जालीदार पिंजड़े का चित्र सजीव हो गया ।


प्र.2 लेखिका ने मोर के विकास को चमत्कारिक क्यों कहा है?

उत्तर- लेखिका ने मोर के विकास को चमत्कारिक कहा है क्योंकि मोर के सिर की कलगी घनी, लम्बी, और चमकीली हो गई थी| चोंच नुकीली और  पैनी हो गयी थी। आँखों में  नीली चमक आ गयी थी और लम्बी नीली-हरी गर्दन में धुपछाँही तरंगे दिखने लगी थीं।


प्र.3 मोर-मोरनी का नामकरण किस आधार पर किया गया?

उत्तर- नीलाभ  ग्रीवा के कारण मोर का नाम नीलकंठ रखा गया और मोरनी सदा मोर की छाया के समान रहती थी इसलिए राधा कहलाई ।


प्र.4 ‘मंथर’ , ‘छाया’, मंद,  'उष्णता'  शब्दों के विपरीतार्थक शब्द लिखिए ।

उत्तर- शब्द  विलोम
मंथर  द्रुत (तेज )
छाया  धूप
          मंद  उच्च,तीव्र
         उष्णता शीतलता

CBSE Class 10/9/8 - English Grammar - Types of Prepositions

Types of Prepositions

I n the earlier post you have learned about forms of preposition. As we know a Preposition is a word place before a Noun (or Pronoun) to show in what relation the person or thing denoted by the Noun stands to something else.

Prepositions are mainly of five types:

① Preposition of Place

② Preposition of Time

③ Preposition of Direction

④ Preposition of Movement

⑤ Preposition of Position

① Preposition of Place: There are three prepositions of places:

⒜ At - used for a point of place (for small towns, villages or less important or small places)

e.g.

At home

At the exit/entrance

At work

He lives at Meharauli in Delhi.

At school

⒝ In - Used for spaces, for large places, countries, large towns, state of rest or position inside anything.

e.g.

He lives in Delhi.

In the mall

He is in his room.

He lives at Panji in Goa.