Practice Set 1.4 Sets Class 9th Mathematics Part I MHB Solution

Practice Set 1.4 Sets Class 9th Mathematics Part I MHB Solution
Practice Set 1.4
Question 1.

If n(A) = 15, n(A ∪ B) = 29, n (A ∩ B) = 7 then n (B) = ?


Answer:

Given: n(A ∪ B) = 29, n(A) = 15 and n (A ∩ B) = 7

As we know, n (A ∪ B) = n(A) + n(B) - n (A ∩ B)


⇒ 7 = 15 + n(B) – 29


⇒ n(B) = -14 - 7


⇒ n(B) = -21



Question 2.

In a hostel there are 125 students, out of which 80 drink tea, 60 drink coffee and 20drink tea and coffee both. Find the number of students who do not drink tea or coffee.


Answer:

Given: n(A) = 80, n(B) = 60 and n (A ∩ B) = x = 20

Total number of students = 125


n(A) = number of students who drink tea


n(B) = number of students who drink coffee


n (A ∩ B) = number of students who drink both tea and coffee


n (A ∪ B) = number of students who drink either tea or coffee



As we know, n (A ∪ B) = n(A) + n(B) - n (A ∩ B)


⇒ n (A ∪ B) = 80 + 60 - 20


⇒ n (A ∪ B) = 140 - 20


⇒ n (A ∪ B) = 120


Then, the number of students who do not drink tea or coffee = 125 – 120


= 5



Question 3.

In competitive exam 50 students passed in English. 60 students passed in Mathematics.40 students passed in both the subjects. None of them fail in both the subjects. Find the number of students who passed at least in one of the subjects?


Answer:

Given: n(A) = 50, n(B) = 60 and n (A ∩ B) = x = 40

n(A) = number of students who passed in English


n(B) = number of students who passed in mathematics


n (A ∩ B) = number of students who passed both subjects


n (A ∪ B) = number of students who passed in at least one of the subject



As we know, n (A ∪ B) = n(A) + n(B) - n (A ∩ B)


⇒ n (A ∪ B) = 50 + 60 - 40


⇒ n (A ∪ B) = 110 - 40


⇒ n (A ∪ B) = 70


Hence, the number of students who passed in at least one of the subject = 70


Question 4.

A survey was conducted to know the hobby of 220 students of class IX. Out of which130 students informed about their hobby as rock climbing and 180 students informed about their hobby as sky watching. There are 110 students who follow both the hobbies. Then how many students do not have any of the two hobbies? How many of them follow the hobby of rock climbing only? How many students follow the hobby of sky watching only?


Answer:

Given: n(A) = 130, n(B) = 180 and n (A ∩ B) = x = 110

Total number of students = 220


n(A) = number of students whose hobby is rock climbing


n(B) = number of students whose hobby is sky watching


n (A ∩ B) = number of students whose hobby is both


n (A ∪ B) = number of students whose hobby is either rock climbing or sky watching



As we know, n (A ∪ B) = n(A) + n(B) - n (A ∩ B)


⇒ n (A ∪ B) = 130 + 180 - 110


⇒ n (A ∪ B) = 310 - 110


⇒ n (A ∪ B) = 200


Then,


(i) The number of students who do not have any of the two hobbies


= 220– 200


= 20


(ii) The number of students whose hobby is rock climbing


= 130– 110


= 20


(iii) The number of students whose hobby is sky watching


= 180– 110


= 70



Question 5.

Observe the given Venn diagram and write the following sets.

i. A ii. B

iii. A ∪ B iv. U

C. A’ vi. B’

vii. (A ∪ B)’



Answer:

(i) A = {x, y, z, m, n}


(ii) B = {p, q, r, m, n}


(iii) (A ∪ B) = { x, y, z, m, n, p, q, r}


(iv) U = { x, y, z, m, n, p, q, r, s, t}


(v) A’ = {p, q, r, s, t}


(vi) B’ = {x, y, z, s, t}


(vii) (A ∪ B)’ = { s, t}

PDF FILE TO YOUR EMAIL IMMEDIATELY PURCHASE NOTES & PAPER SOLUTION. @ Rs. 50/- each (GST extra)

HINDI ENTIRE PAPER SOLUTION

MARATHI PAPER SOLUTION

SSC MATHS I PAPER SOLUTION

SSC MATHS II PAPER SOLUTION

SSC SCIENCE I PAPER SOLUTION

SSC SCIENCE II PAPER SOLUTION

SSC ENGLISH PAPER SOLUTION

SSC & HSC ENGLISH WRITING SKILL

HSC ACCOUNTS NOTES

HSC OCM NOTES

HSC ECONOMICS NOTES

HSC SECRETARIAL PRACTICE NOTES

2019 Board Paper Solution

HSC ENGLISH SET A 2019 21st February, 2019

HSC ENGLISH SET B 2019 21st February, 2019

HSC ENGLISH SET C 2019 21st February, 2019

HSC ENGLISH SET D 2019 21st February, 2019

SECRETARIAL PRACTICE (S.P) 2019 25th February, 2019

HSC XII PHYSICS 2019 25th February, 2019

CHEMISTRY XII HSC SOLUTION 27th, February, 2019

OCM PAPER SOLUTION 2019 27th, February, 2019

HSC MATHS PAPER SOLUTION COMMERCE, 2nd March, 2019

HSC MATHS PAPER SOLUTION SCIENCE 2nd, March, 2019

SSC ENGLISH STD 10 5TH MARCH, 2019.

HSC XII ACCOUNTS 2019 6th March, 2019

HSC XII BIOLOGY 2019 6TH March, 2019

HSC XII ECONOMICS 9Th March 2019

SSC Maths I March 2019 Solution 10th Standard11th, March, 2019

SSC MATHS II MARCH 2019 SOLUTION 10TH STD.13th March, 2019

SSC SCIENCE I MARCH 2019 SOLUTION 10TH STD. 15th March, 2019.

SSC SCIENCE II MARCH 2019 SOLUTION 10TH STD. 18th March, 2019.

SSC SOCIAL SCIENCE I MARCH 2019 SOLUTION20th March, 2019

SSC SOCIAL SCIENCE II MARCH 2019 SOLUTION, 22nd March, 2019

XII CBSE - BOARD - MARCH - 2019 ENGLISH - QP + SOLUTIONS, 2nd March, 2019

HSC Maharashtra Board Papers 2020

(Std 12th English Medium)

HSC ECONOMICS MARCH 2020

HSC OCM MARCH 2020

HSC ACCOUNTS MARCH 2020

HSC S.P. MARCH 2020

HSC ENGLISH MARCH 2020

HSC HINDI MARCH 2020

HSC MARATHI MARCH 2020

HSC MATHS MARCH 2020

SSC Maharashtra Board Papers 2020

(Std 10th English Medium)

English MARCH 2020

HindI MARCH 2020

Hindi (Composite) MARCH 2020

Marathi MARCH 2020

Mathematics (Paper 1) MARCH 2020

Mathematics (Paper 2) MARCH 2020

Sanskrit MARCH 2020

Sanskrit (Composite) MARCH 2020

Science (Paper 1) MARCH 2020

Science (Paper 2)

MUST REMEMBER THINGS on the day of Exam

Are you prepared? for English Grammar in Board Exam.

Paper Presentation In Board Exam

How to Score Good Marks in SSC Board Exams

Tips To Score More Than 90% Marks In 12th Board Exam

How to write English exams?

How to prepare for board exam when less time is left

How to memorise what you learn for board exam

No. 1 Simple Hack, you can try out, in preparing for Board Exam

How to Study for CBSE Class 10 Board Exams Subject Wise Tips?

JEE Main 2020 Registration Process – Exam Pattern & Important Dates

NEET UG 2020 Registration Process Exam Pattern & Important Dates

How can One Prepare for two Competitive Exams at the same time?

8 Proven Tips to Handle Anxiety before Exams!

BUY FROM PLAY STORE

DOWNLOAD OUR APP

HOW TO PURCHASE OUR NOTES?

S.P. Important Questions For Board Exam 2021

O.C.M. Important Questions for Board Exam. 2021

Economics Important Questions for Board Exam 2021

Chemistry Important Question Bank for board exam 2021

Physics – Section I- Important Question Bank for Maharashtra Board HSC Examination

Physics – Section II – Science- Important Question Bank for Maharashtra Board HSC 2021 Examination