# NCERT Solutions for Class 12 Maths Chapter 7 Exercise 7.9

NCERT Solutions for Class 12 Maths Chapter 7 Exercise 7.9 Integrals in English Medium as well as हिंदी मीडियम free to download in PDF or view online. Download CBSE Apps based on Latest NCERT Solutions for 2019-20.

 Class 12: Maths – गणित Chapter 7: Integrals Exercise 7.9

## NCERT Solutions for Class 12 Maths Chapter 7 Exercise 7.9

### 12 Maths Exercise 7.9 Solutions

#### NCERT Solutions for Class 12 Maths Exercise 7.9 in English

NCERT Solutions for Class 12 Maths Chapter 7 Exercise 7.9 Integrals in English Medium is given below. Visit to हिंदी मीडियम or Class 12 Maths Chapter 7 main page or Top of the page.

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##### NCERT Solutions for Class 12 Maths Exercise 7.9 in Hindi

NCERT Solutions for Class 12 Maths Chapter 7 Exercise 7.9 Integrals in Hindi Medium is given below. Visit to English Medium or Class 12 Maths Chapter 7 main page or Top of the page.

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###### Questions for Practice
1. Let A = {1, 2, 3… 12} and R be a relation in A × A defined by (a, b) R (c, d) if ad = bc ∀ (a, b), (c, d) ∈ A × A. Prove that R is an equivalence relation. Also obtain the equivalence class [(3, 4)].
2. 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.
3. If ‘*’ is a binary operation on R defined by a * b = a + b + ab. Prove that * is commutative and associative. Find the identify element. Also show that every element of R is invertible except –1.

###### Important Questions
• 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.
• Let N denote the set of all natural numbers and R be the relation on N × N defined by (a, b) R (c, d) if ad (b + c) = bc (a + d). Show that R is an equivalence relation.
• A man has ₹ 1500 to purchase two types of shares of two different companies S1 and S2. Market price of one share of S1is ₹ 180 and S2 is ₹120. He wishes to purchase a maximum of ten shares only. If one share of type S1 gives a yield of ₹ 11 and of type S2 yields ₹ 8 then how much shares of each type must be purchased to get maximum profit? And what will be the maximum profit?