# Important Questions for CBSE Class 11 Maths Chapter 6 - Linear Inequalities

## CBSE Class 11 Maths Chapter-6 Important Questions - Free PDF Download

Free PDF download of Important Questions with solutions for CBSE Class 11 Maths Chapter 6 - Linear Inequalities prepared by expert Maths teachers from latest edition of CBSE(NCERT) books. CoolGyan.Org to score more marks in your Examination.

1 Marks Questions

1. Solve

Ans.

2. Solve when is a real no.

Ans.

3. Solve the inequality

Ans.

4. If then

Ans.

5. Solve the inequality

Ans.

6. Solution set of the in inequations and is.

Ans.

7. Solve. Show the graph of the solution on number line.

Ans.

8. Solve the inequality.

Ans.

9. Solve when is an integer.

Ans.

10. Solve when is a natural no.

Ans.

Solution set of the inequality

11. Solve the inequality

Ans.

12. Solve when is an integer.

Ans.

When is an integer the solutions of the given inequality are……-4,-3,-2,-1, 0, 1

4 Marks Questions

1. Solve graphically

Ans.

Put (0,0)in eq. (i)

false.

2. Ravi obtained 70 and 75 mark in first unit test. Find the minimum marks he should get in the third test to have an average of at least 60 marks.

Ans. Let Ravi secure marks in third test

ATQ

3. Find all pairs of consecutive odd natural no. both of which are larger than 10 such that their sum is less than 40.

Ans. Let and be consecutive odd natural no.

ATQ

From (i) and (ii)

4. A company manufactures cassettes and its cost equation for a week is C=300+1.5and its revenue equation is R=2, where is the no. of cassettes sold in a week. How many cassettes must be sold by the company to get some profit?

Ans. Profit = revenue-cost

5. The longest side of ais 3 times the shortest side and the third side is 2 cm shorter than the longest side. If the perimeter of theis at least 61 cm find the minimum length of the shortest side.

Ans. Let shortest side be cm then the longest side is cm and the third side cm.

ATQ

Length of shortest side is 9 cm.

6. In drilling world’s deepest hole it was found that the temperature T in degree Celsius, km below the surface of earth was given by At what depth will the tempt. Be between c and

Ans. Let km is the depth where the tempt lies between and

7. A man wants to cut three lengths from a single piece of board of length 91 cm. The second length is to be 3 cm longer than the shortest and the third length is to be twice as long as the shortest. What are the possible lengths of the shortest board if the third piece is to be at least 5 cm longer than the second.

Ans. Let the shortest length be cm, then second length is (+3) cm and the third length is 2 cm.

ATQ

Again ATQ

8. The water acidity in a pool is considered normal when the average pH reading of three daily measurements is between 7.2 and 7.8 If the first pH reading are 7.48 and7.85, find the range of pH value for the third reading that will result in the acidity level being normal.

Ans. Let third reading be then

9. A plumber can be paid under two schemes as given below.

I: Rs 600 and Rs 50 per hr.

II: Rs 170 per hr.

If the job takes n hr. for what values of n does the scheme I gives the plumber the better wages.

Ans. For better wages earning should be more then

Thus for better wages scheme working hr. should be less than 5 hr.

 0 15 20 0

 0 20 0 40

10. Solve the inequalities graphically

Ans.

 0 4 3 0

Put in eq. ………

false

11. Solve graphically

Ans.

Put (1,0) in eq. (i)

false

12. Solve graphically

Ans.

 0 2 3 0

Put in eq. ……….

which is false

6 Marks Questions

1. IQ of a person is given by the formula

Where MA is mental age and CA is chronological age. If 80 IQ140 for a group of 12yr old children, fond the range of their mental age.

Ans. IQ (Given)

MA

MA

2. Solve graphically

Ans.

 0 15 20 0

 0 20 0 40

3. A manufacturer has 600 litre of a 12% sol. Of acid. How many litres of a 30% acid sol. Must be added to it so that acid content in the resulting mixture will be more than 15% but less than 18%.

Ans. Let litres of 30% acid sol. Is required to be added.

of of and

of of

and

i.e.

4. Solve graphically

Ans.

 3 5 0 1

 0 4 3 0

5. A sol. Of 8% boric acid is to be diluted by adding a 2% boric acid sol. to it. The resulting mixture is to be more than 4% but less than 6% boric acid. If we have 640 litres of the 8% sol. how many litre of the 2% sol. will have to be added.

ATQ of ofof

And of of of

From (i) and (ii)

6. Solve graphically

Ans.

 0 10 5 0

 0 1 1 0

 0 2 0 2

7. How many litres of water will have to be added to 1125 litres of the 45% sol. Of acid so that the resulting mixture will contain more than 25%but less than 30% acid content.

Ans. Let litre of water be added to 1125 litre of 45 acid sol.

of of

of of

8. Solve graphically

Ans.

 0 50 75 0

 0 80 20 0