# NCERT Solutions for Class 12 Maths Chapter 7 Exercise 7.4

NCERT Solutions for Class 12 Maths Chapter 7 Exercise 7.4 Integrals in English Medium as well as हिंदी मीडियम free to download in PDF or view online updated for 2020-21 for all boards using latest NCERT Books.

Download Solutions Apps based on latest NCERT Solutions for 2020-21. If you are facing any problem to use the contents, please contact us without any hesitation. We will help you as much as possible.## NCERT Solutions for Class 12 Maths Chapter 7 Exercise 7.4

Class: | 12 |

Subject: | Maths |

Chapter 7: | Exercise 7.4 |

### 12th Maths Exercise 7.4 Solutions

NCERT Solutions for Class 12 Maths Chapter 7 Exercise 7.4 Integrals in English Medium is given below updated for new academic session 2020-2021. Download NCERT Books and Offline apps based on the latest CBSE Syllabus for all boards who are using NCERT books as course books. Visit to Discussion forum to grow your knowledge and ask questions regarding to NIOS or CBSE Board.

### Exercise 7.4 Solutions in Hindi & English

#### Questions from Board Papers

1. A man takes a step forward with probability 0.4 and backward with probability 0.6. Find the probability that at the end of eleven steps he is one step away from the starting point.

2. Suppose that 10% of men and 5% of women have grey hair. A grey haired person is selected at random. What is the probability that the selected person is male assuming that there are 60% males and 40% females?

3. Find P (A/B) if P(A)= 0.4, P(B)= 0.8 and P (B/A)= 0.6

4. Find P (A ∩ B) if A and B are two events such that P(A) = 0.5, P(B) = 0.6 and P (A ∪ B) = 0.8

5. A soldier fires three bullets on enemy: The probability that the enemy will be killed by one bullet is 0.7. What is the probability that the enemy is still alive?

##### Important Questions for Practice

1. Bag A contains 4 red, 3 white and 2 black balls. Bag B contains 3 res, 2 white and 3 black balls. One ball is transferred from bag A to bag B and then a ball is drawn from bag B. The ball so drawn is found to be red. Find the probability that the transferred ball is black.

2. Three coins are tossed once. Find the probability of getting at least one head.

3. A diet for a sick person must contain at least 4000 units of vitamins, 50 units of minerals and 1400 units of calories. Two foods A and B are available at a cost of ₹5 and ₹4 per unit respectively. One unit of food A contains 200 units of vitamins, 1 unit of minerals and 40 units of calories whereas one unit of food B contains 100 units of vitamins, 2 units of minerals and 40 units of calories. Find what combination of the food A and B should be used to have least cost but it must satisfy the requirements of the sick person. What is balanced diet and what is the importance of balanced diet in daily life?

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