Ample book class8 chapter 2 objectives solutions
Answers
Answer:
1.Which of the following is not a linear equation in one variable?
A. 33
B. 33(x+y)
C. 33x
D. 33y
Answer: B
Explanation: In 33(x+y), x and y are two variables.
2. The solution of 2x-3=7 is:
A. 5
B. 7
C. 12
D. 11
Answer: A
Explanation: 2x-3=7
2x=7+3=10
x=10/2 = 5
Explanation:
The solution of 2y + 9 = 4 is:
A. 9/2
B. 4/9
C. -⅖
D. -5/2
Answer: D
Explanation: 2y+9 = 4
2y = 4-9 = -5
y=-5/2
4. The solution of y/5 = 10 is:
A. 15
B. 10
C. 50
D. 5
Answer: C
Explanation: y/5 = 10
y = 5×10 = 50
5. What should be added to -7/3 to get 3/7?
A. 21/58
B. 58/21
C. 47/21
D. 50/21
Answer: B
Explanation: Let the number be x
-7/3+x = 3/7
x=3/7+7/3 = (9+49)/21 = 58/21
6. The perimeter of rectangle is 20cm. If the length of rectangle is 6cm, then its breadth will be:
A. 4 cm
B. 6 cm
C. 10 cm
D. 14 cm
Answer: A
Explanation: Perimeter of rectangle = 2(Length+Breadth)
20 = 2(6+x)
6+x = 20/2
6+x = 10
x = 10-6
x=4 cm
7. The age of father is three times the age of son. If the age of son is 15 years old, then the age of father is:
A. 50 years
B. 55 years
C. 40 years
D. 45 years
Answer: D
Explanation: Let age of the father is x
Given: x = 3 × (age of son) = 3 × (15) = 45 years
8. The difference between two whole numbers is 66. The ratio of the two numbers is 2 : 5. The two numbers are:
A. 60 and 6
B. 100 and 33
C. 110 and 44
D. 99 and 33
Answer: C
Explanation: Let the two numbers be 2x and 5x since they are in the ratio of 2:5.
The difference between 5x and 2x = 66
5x – 2x = 66
3x = 66
x = 22
Hence, 2x = 2(22) = 44 and 5x = 5(22) = 110.
9. Three consecutive integers add up to 51. The integers are:
A. 16,17,18
B. 15,16,17
C. 17,18,19
D. 18,19,20
Answer: A
Explanation: Let the three consecutive integers be x, x+1, x+2
x+(x+1)+(x+2) = 51
3x+3 = 51
3x = 51 – 3
x = 48/3 = 16
x+1 = 16+1=17
x+2 = x+2 = 18
10. The solution for 3m = 5m – (8/5) is:
A. 8/5
B. ⅘
C. 5/4
D. 4/3
Answer: B
Explanation: 3m = 5m – (8/5)
8/5 = 5m – 3m
2m = 8/5
m = 8/10 = 4/5