CBSE Class 8 Mathematics Linear Equations Assignment Set B

Very Short Answer type Questions

Question. Sum of two numbers is 30. If one number is twice the other, form an equation for finding the numbers.
Answer : 2x + x = 30.

Question. Find x if 2x + 5 = x + 25.
Answer : 20.

Question. Find the value of x/2 + x/3 + x/4
Answer : 13x/12

Question. Give a number which is always even in terms of variable x.
Answer : 2x

Question. Preeti has three more dolls than Renu. If there are 11 dolls in all, how many dolls does each have.
Answer : 7, 4

Question. If x = n + 1 then find the value of (2x + 5)
Answer : 2n + 7

Question. Form an equation : 5 added to twice a number is 135.
Answer : 2x + 5 = 135

Question. Ratio of three angles of a triangle is 1 : 2 : 3. Find the angles.
Answer : 30°, 60°, 90°

Question. Ankit covered (1/2) of the distance by metro train, (1/3)^rd of the distance by bus and rest of 6 km by car for moving from Dwarka to South Extension. Find the total distance covered?
Answer : 36 km

Question. If 2x + 9 = 47. Find x.
Answer : 19

Question. What type of number is (2x + 1). [odd or even].
Answer : Odd

Question. If the length of a rectangle is 5 more than its breadth (x). What is the perimeter of the rectangle?
Answer : 4x + 10.

Question. 3(x + 4) = x + 38 find x.
Answer : 13

Question. I guessed a number (x) then added 10 to it. Give the expression for double of it.
Answer : 2(x + 10)

Question. If x = n/3 + 2 than 3x - 1 = __________.
Answer : n + 5.

1. The present age of Sahil’s mother is three times the present age of Sahil. After 5 years their ages will add to 66 years. Find their present ages.

2. The ages of Rahul and Anshul are in ratio 5:7. Four years later the sum of these ages will be 56 years .What are their present ages?

3. Fifteen years from now Ravi’s age will be four times his present age. What is Ravi‘s present age?

4. Rahul’s father is 26 years younger than Rahul’s grandfather and 29 years older than Rahul. The sum of the ages of all the three is 135 years. What is the age of each one of them ?

5. Shobo’s mother’s present age is 6 times Shobo’s present age. Shobo’s age five years from now will be one-third of his mother’s present age. What are their present ages?

6. A grand-father is 10 times older than his grand-daughter. He is also 54 years older than her. What is his present age ?

7. Aman’s age is three times his son’s age.10 years ago he was 5 times his son’s age. Find their present ages.

8. Two years ago Dilip was three times as old is his son and two years hence twice his age will be equal to five times that of his son. Find their present ages.

9. Present ages of Annu and Raj are in the ratio 4:5. Eight years from now the ratio of their ages will be 5:6. Find their present ages.

10. Ages of Mohan and Sohan are in the ratio 3:4. Find their present ages if sum of their ages is 35 years.

11. Three consecutive integers add up to 51. What are these integers?

12. Sum of three consecutive multiples of 11 is 363. Find these multiples.

13. The sum of three consecutive multiples of 8 is 888. Find the multiples.

14. Three consecutive integers are such that when they are taken in increasing order and multiplied by 2, 3 and 4 respectively, they add up to 74. Find these numbers.

15. Two numbers are in the ratio 5:3. If they differ by 18, what are the numbers?

16. Sum of two numbers is 95. If one exceed the other by 15. Find the numbers.

17. The no. of boys and girls in a class is in the ratio 7:5. The number of boys is 8 more than the number of girls. What is the total class strength?

18. A positive number is 5 times another number. If 21 is added to both the numbers, then one of the new numbers becomes twice the other new number, Find the numbers?

19. Lakshmi is a cashier in a bank. She has currency notes of denomination Rs 100, Rs 50 and Rs 10 respectively, the ratio of these notes is 2:3:5. The total cash with Lakshmi is Rs. 4, 00,000. How many notes of each denomination does she have?

20. Devasi has a total of Rs 590 as currency notes in the denominations of Rs 50, Rs 20 and Rs 10. The ratio of the number of Rs 50 notes and Rs 20 notes is 3:5. If she has a total of 25 notes in all, how many notes of each denomination does she have?

21. I have a total of Rs. 300 in coins of denomination Rs 1, Rs 2, Rs 5. The number of Rs 2 coins is 3 times the number of Rs 5 coins. The total number of coins is 160. How many of each denomination are with me?

22. The organizers of an essay competition decide that the winner in the competition gets a prize of Rs 100 and a participant who does not win will get Rs 25 . The total prize money distributed is Rs. 3,000. Find the no. of winners, if the total no. of participants is 63.

23. Sum of the digits of a two-digit number is 9. When we interchange the digits, it is found that the resulting new number is greater than the original by 27. What is that two –digit number?

24. One of the two digits of a two digit number is three times the other digit. If you interchange the digits of this two-digit number and add the resulting number to the original number, you get 88. What is the original number?

25. Half a herd of deer are grazing in the field and three fourth of them are playing nearby. The rest 9 are drinking water from the pond. Find the number of deer in the herd.

26. There is a narrow rectangular plot, reserved for a school, in Mahuli village. The length & breadth of the plot are in the ratio 11:4. At the rate of Rs. 100/metre it will cost the village panchayat Rs 75,000 to fence. What are the dimensions of the plot?

27. Hasaan buys two kinds of cloth material for school uniforms. Shirt material that costs him Rs 50 per meter and trouser material that costs him Rs 90 per meter. For every 3 meters of the shirt material, he buys 2 meters of the trouser material. He sells the materials at 12% and 10% profit respectively. If his total sale is Rs 36600, how much trouser material did he buy?

28. The denominator of a rational number is greater than its numerator by 8. If the numerator is increased by 17 and the denominator is decreased by 1 the number obtained is 3/2. Find the rational number. 

29. The sum of the digits of a two digit numbers is 10. If the number formed by reversing the digits is less than the original number by 36, find the original number.

Questions carrying 1 Mark each :-

Q.1 By which sign the algebraic expressions are connected to form an equation?

Q.2 Find the solution of 2x+5= 7.

Questions carrying 2 Marks each :

Q.3 Solve for y :-
ÿ/xx = 2/5

Q.4 Find the solution of
0/2 + 55550 + x5 = 300

Q.5 Anumber is seven times the other number. If their sum is 96, find the numbers.

Questions carrying 3 marks each:-

Q.6 If the same number is added to both the numerator and denominator of a fraction x/5 ,then the result is 1/4. Find the number.

Q.7 The perimeter of a rectangle is 52cm. If its widthis 2cm more than one-third of its length, find the dimensions of the rectangle.

Q.8 The sum of three consecutive multiplies of 7 is 777. Find these multiples.

Q.9 Meena's mother is four times as old as Meena. After five years, her mother will be three times as old as she will be then. What are their present ages?

Questions carrying 6 marks each :-

Q.10 The sum of the digits of a two digit number is 10. If the number formed by reversing the digits is less than the original number by 36, find the number.

Q.11 A bag contains coins of denomination of Rs. 5 and Rs. 2. The total value of these coins is Rs. 1272. If the number of two rupee coins is 15% of the five rupee coins, find the number of coins of each denomination.

Multiple choice Questions carrying 1 mark each :-

Q.12 In a linear equation, the highest power of the variableis :-
a) One
b) two
c) Three
d) Zero

Q.13 An equation of the form ax + b = c, where a, b and c are numbers, a ÿ 0 and x is the variable; represents a
a) linear equation
b) linear equation in one variable
c) linear equation in two variables
d) None of these

Questions carrying 1 Mark each :-