Linear Equations In One Variable – Chapter 2/ MCQ

CBSE CLASS 8 MATHEMATICS
Linear Equations In One Variable – Chapter2/ MCQ
Multiple Choice Questions

Choose the correct answer from the options given below:

1. If half of a number added to 25 is 100, then the number is —————–
A. 150
B. 75
C. 100
2. Find the solution of 3x – 7 = 20.
A. 9
B. 10
C. 11
3. The solution of the equation 3y – 8 = 13 is ———-
A. 4
B. 7
C. 9
4. Which of the following is not a linear equation?
A. 2x = 64
B. x+ 45
C. 5x – 35 = 0
5. The sum of a number and its twice is 300. What is the number?
A. 50
B. 100
C. 150
6. Aman’s age is three times his son’s age. Ten years ago he was five times his son’s age. What is the present age of Aman?
A.6 years
B. 16 years
C. 60 years
7. Solve 2x-1 = 14-x.
A.5
B. 6
C. 7
8. The solution of the equation 6x =0 is —————
A. 0
B. 1
C. 6
9. The value of x for which the expressions 2x -5 and 3(x-5) become equal is ————–
A. 5
B. 10
C. 15
10. Make an algebraic expression for the following statement:
11 is subtracted from twice the number x.
A. x – 11
B. 11 – 2x
C. 2x – 11.

ANSWERS:

1. 150
[Explanation: Let the number be x.
Given x/2 + 25 = 100
x/2 = 100 – 25 = 75
x = 75 x 2 = 150]

2. 9
[Explanation: 3x – 7 = 20
3x = 20 +7 = 27
x = 27/3 =9]

3. 7
[Explanation: 3y – 8 = 13
3y = 13 + 8 = 21
y = 21/3 = 7]

4. x + 45

5. 100
[Explanation: Let the number be x.
Give x + 2x = 300
3x = 300
x = 300/3 = 100]

6. 60 years
[Explanation: Let age of son = x years
Aman’s age = 3x
Ten years ago Aman’s age = 3x – 10
Ten years ago Aman’s son’s age = x – 10
Given 3x -10 = 5(x – 10)
3x – 10 = 5x – 50
3x – 5x = -50 + 10
-2x = -40
x = -40/-2 = 20 years
Aman’s age = 3x = 60 years.]

7. 5
[Explanation: 2x -1 = 14 – x
2x +x = 14 +1
3x = 15
x = 15/3 = 5]

8. 0

9. 10
[Explanation: 2x – 5 = 3(x -5)
2x – 5 = 3x – 15
2x – 3x = -15 + 5
-x = -10
x = 10]

10. 2x – 11.