# NCERT Solutions for Class 12 Maths Chapter 7 Exercise 7.8

NCERT Solutions for Class 12 Maths Chapter 7 Exercise 7.8 Integrals in English Medium as well as हिंदी मीडियम free to download in PDF or view online updated for new session 2020-21 for those using NCERT Books.

Download NCERT Solutions Apps based on Latest NCERT Solutions for CBSE, MP Board, UP Board and other boards following CBSE Syllabus 2020-2021.## NCERT Solutions for Class 12 Maths Chapter 7 Exercise 7.8

Class: | 12 |

Subject: | Maths |

Chapter 7: | Exercise 7.8 |

### 12th Maths Exercise 7.8 Solutions

NCERT Solutions for Class 12 Maths Chapter 7 Exercise 7.8 Integrals in PDF form to free download in Hindi and English are given below. Download NCERT Books 2020-2021 and offline apps based on latest CBSE Syllabus.

### Exercise 7.8 Solutions in Hindi & English

#### Questions from Board Papers

1. There are two types of fertilisers A and B. A consists of 10% nitrogen and 6% phosphoric acid and B consists of 5% nitrogen and 10% phosphoric acid. After testing the soil conditions, a farmer finds that he needs at least 14 kg of nitrogen and 14 kg of phosphoric acid for his crop. If A costs ₹ 6 per kg and B costs ₹ 5 per kg, determine how much of each type of fertiliser should be used so that nutrient requirements are met at minimum cost. What is the minimum cost? What values are being promoted here?

2. Three critics review a book. Odds in favour of the book are 5:2, 4:3 and 3:4 respectively for the three critics. Find the probability that the majority are in favour of the book.

3. Two tailors A and B earn ₹ 150 and ₹ 200 per day respectively. A can stitch 6 shirts and 4 pants per day, while B can stitch 10 shirts and 4 pants per day. How many days shall each work if it is desired to produce atleast 60 shirts and 32 pants at a minimum labour cost? Solve the problem graphically.

##### Important Questions for Practice

1. A trust invested some money in two type of bonds. The first bond pays 10% interest and second bond pays 12% interest. The trust received ₹ 2800 as interest. However, if trust had inter changed money in bonds, they would have got ₹ 100 less as interest using matrix method, find the amount invested in each bond by the trust.

2. A dealer wishes to purchase a number of fans and sewing machines. He has only ₹ 5760 to invest and has space for atmost 20 items. A fan and sewing machine cost ₹ 360 and ₹ 240 respectively. He can sell a fan at a profit of ₹ 22 and sewing machine at a profit of ₹ 18. Assuming that he can sell whatever he buys, how should he invest his money to maximise his profit?

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