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Published on: 12/08/2019
Linear Equations in One Variable
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1.
The numerator of a fraction is 6 less than the denominator. If 1 is added to both numerator and denominator, it becomes \(\frac { 1 }{ 2 } \) then find the fraction.
2.
Solve the following equations and check your result. \(\frac { 2x }{ 3 } +1=\frac { 7x }{ 15 } +3\)
3.
Solve the following equations 6 = Z + 2
4.
Two different equations can never have the same answer.
5.
In a two-digit number, the unit's place digit is x. If the sum of digits be 9, then the number is (10x - 9).
6.
If 16x = 80, then 18x = 90
7.
In the equation 13x - 4 = 9, transposing -4 to RHS, we get 13x = 5.
8.
When we divide by same non-zero number on both sides (i.e. LHS and RHS) of an equation. Then, balance is disturbed.
9.
Simplify and solve the following linear equations:
3 (5z - 7) - 2 (9z - 11) = 4 (8z - 13) - 17
10.
Three consecutive integers are such that when they are taken in increasing order and multiplied by 2, 3 and 4 respectively, they add upto 74. Find these numbers.
11.
If you Subtract \(\frac { 1 }{ 2 } \) from a number and multiply the result by \(\frac { 1 }{ 2 } \) you get \(\frac { 1 }{ 8 } \) what is the number?
12.
Solve the following linear equations:
m-\(\frac{m-1}{2}\)=1-\(\frac{m-2}{2}\)
13.
In a rare coin collection, there is one gold coin for every three non-gold coins. If 10 more gold coins are added to the collection, the ratio of gold coins to non-gold coins becomes 1 : 2. Based on the information, find the total number of coins in the collection now?
14.
The organisers of an essay competition decide that a winner in the competition gets a prize of Rs. 100 and a participant who does not win, gets a prize of Rs. 25. The total prize money distributed is Rs. 3000. Find the number of winners, if the total number of participants is 63.
15.
10 years ago, I was 'x' years old. After 10 years, my age will be:
(x + 20) years
(x - 20) years
(x + 10) years
(x - 10) years
16.
If \({2\over 5}x=\)4; then which of the following is the value of x?
10
-10
\({-8\over 5}\)
\({8\over 5}\)
17.
A linear equation in one variable has
only one solution
no solution
two solutions
more than two solutions
18.
The Solution of the equation ax+b = 0 is
\(x=\frac { a }{ b } \)
x = -b
\(x=\frac { -b }{ a } \)
\(x=\frac { b }{ a } \)
19.
An equation which, when reduced to a simple form, involve no power of the variable quantity higher than _______ is called a simple equation.
20.
If 4t - 3 - (3t + 1)= 5t - 4, then the root of t is.....
21.
19 is subtracted from the product of P and 14. The result is 21. The value of P is
22.
A term of an equation can be transposed to the other side by changing its.........
23.
In a linear equation, ............power of the variable appearing in the equation is one.
24.
\({x-1\over 8}={2x+3\over 15}\)
25.
\({x\over 3}+{1\over 4}={x\over 2}-{1\over 5}\)
26.
\(\frac { 8 }{ x } =\frac { 5 }{ x-1 } \)
27.
\(\frac { 31 }{ 6 } \)
28.
7
1.
\(\frac { 5 }{ 11 } \)
2.
\(\frac { 2x }{ 3 } +1=\frac { 7x }{ 15 } +3\)
\(\Rightarrow\) \(\frac { 2x }{ 3 } +1=\frac { 7x }{ 15 } - 3\) [transposing \(\frac { 7x }{ 15 } \) to LHS and 1 to RHS]
\(\Rightarrow\)\(\frac { 10x-7x }{ 15 } =2\) [LCM of 3 and 15 = 15]
\(\Rightarrow\) \(\frac { 3x }{ 15 } =2\Rightarrow \frac { 3x }{ 15 } x5=2x5\)
\(\Rightarrow\) \(\frac { 15x }{ 15 } \)=2 x 5
x = 2 x 5 \(\Rightarrow\) x = 10
which is the required solution.
3.
We have 6 = z + 2
\(\Rightarrow\) 6 - 2 = z [transposing 2 from RHS to LHS]
\(\Rightarrow\) 4 = z \(\Rightarrow\) z = 4, Which is the Required solution
4.
(b)
5.
(b)
6.
(a)
7.
(b)
8.
(b)
9.
3 (5z - 7) - 2 (9z - 11) = 4 (8z - 13) - 17
We have
3(5z -7) - 2(9z -11) = 4(8z -13) -17
\(\Rightarrow\)15z - 21 - 18z + 22 = 32z - 52 - 17
\(\Rightarrow\)- 3z + 1 = 32z - 69
\(\Rightarrow\)- 3z - 32z = - 69 - 1
Transposing 32z to LHS and 1 to RHS
\(\Rightarrow\)- 35z = - 70
\(\Rightarrow\)z = -\(\frac{-70}{-35}\)=2
Dividing both sides by - 35 This is the required solution.
10.
Let the three consecutive integers be x, (x + 1)and (x + 2).
According to the question,
\(\Rightarrow\) 2x + 3 (x + 1)+ 4 (x + 2) = 74
\(\Rightarrow\) 2x + 3x + 3 + 4x + 8 = 74
\(\Rightarrow\)9x + 11 = 74 \(\Rightarrow\) 9x = 74 -11 [transposing 11 to RHS]
\(\Rightarrow\) 9x = 63 \(\Rightarrow\) x = \(\frac { 63 }{ 9 } \) = 7 [dividing both sides by 9]
\(\therefore\) First integer = x = 7
Second integer = x+ 1= 7 + 1= 8
and third integer = x + 2 = 7 + 2 = 9
Hence, the required integers are 7,8 and 9.
11.
Let the number be x
After subtracting \(\frac { 1 }{ 2 } \) from this number, we get Number \(\left( x-\frac { 1 }{ 2 } \right) \)
Now, multiply it by \(\frac { 1 }{ 2 } \) We get number = \(\frac { 1 }{ 2 } \) \(\left( x-\frac { 1 }{ 2 } \right) \)
According to the Questions
\(\frac { 1 }{ 2 } \left( x-\frac { 1 }{ 2 } \right) =\frac { 1 }{ 8 } \Rightarrow \frac { 1 }{ 2 } \left( \frac { 2x-1 }{ 2 } \right) =\frac { 1 }{ 8 } \Rightarrow \frac { 2x-1 }{ 4 } =\frac { 1 }{ 8 } \)
\(\Rightarrow\) \(2x-1=\frac { 1 }{ 8 } \times 4\) [multiplying both sides by 4]
\(\Rightarrow\) \(2x-1=\frac { 1 }{ 2 } \Rightarrow 2x=\frac { 1 }{ 2 } +1\) [transposing -1 to RHS]
\(\Rightarrow\) \(2x=\frac { 1 }{ 2 } +\frac { 1 }{ 1 } \Rightarrow 2x=\frac { 1+2 }{ 2 } \) [LCM of 2 and 1 is 2]
\(\Rightarrow\) \(2x=\frac { 3 }{ 2 } \Rightarrow x=\frac { 3 }{ 2\times 2 } =\frac { 3 }{ 4 } \) [dividing both sides by 2]
Hence, the required number is \(\frac { 3 }{ 4 } \)
12.
m-\(\frac{m-1}{2}\)=1-\(\frac{m-2}{2}\)
We have m-\(\frac{m-1}{2}\)=1-\(\frac{m-2}{2}\)
It is a linear equation since it involves linear expressions only.
\(\Rightarrow\) m-\(\frac{m}{2}+\frac{1}{2}\)=1-\(\frac{m}{3}+\frac{1}{3}\)
\(\Rightarrow\) m-\(\frac{m}{2}+\frac{m}{3}\)=1+\(\frac{2}{3}+\frac{1}{2}\)
Transposing -\(\frac{m}{3}\)to LHS and \(\frac{1}{2}\)to RHS
\(\Rightarrow\) \(\frac { 6m-3m+2m }{ 6 } =\frac { 6+4-3 }{ 6 } \)
Taking LCM
\(\Rightarrow\) \(\frac { 5m }{ 6 } =\frac { 7 }{ 6 } \)
\(\Rightarrow\) m = \(\frac { 7 }{ 6 } \times \frac { 6 }{ 5 } =\frac { 7 }{ 5 } \)
Multiplying both sides by \(\frac{6}{5}\)
This is the required solution.
13.
Let the number of gold coins initially be x
Then, the number of non-gold coins be 3x. When,
10 more gold coins added
Then, the total number of gold coins = (10 + x)
Then, according to the question , \(\frac { (10+x) }{ 3x } =\frac { 1 }{ 2 } \)
\(\Rightarrow\) 2 (10 + x) = 3x \(\Rightarrow\) 20 + 2x = 3x \(\Rightarrow\) x = 20
Then, total number of coins at last = 3x + 10 + x = 4x + 10 = 4 x 20 + 10 = 90
14.
Given, total number of participants is 63.
Let the number of winners be x.
.\(\therefore\) The number of non-winners = (63 - x)
Prize money given to winners = 100x
Prize money given to non-winners = 25 (63 - x)
According to the question,
Total prize money = 3000
\(\Rightarrow\) 100x + 25 (63 - x) = 3000
\(\Rightarrow\) 100x + 1575 - 25x = 3000
\(\Rightarrow\) 75x + 1575 = 3000
\(\Rightarrow\) 75x = 3000 -1575 [transposing 1575 to RHS]
\(\Rightarrow\) 75x = 1425 \(\Rightarrow\) \(\frac { 1425 }{ 75 } \)
x = 19
Hence, the number of winners are 19
15.
(a)
(x + 20) years
16.
(a)
10
17.
(a)
only one solution
18.
(c)
\(x=\frac { -b }{ a } \)
19.
( )
One
20.
( )
4t - 3 - (3t + 1)= 5t - 4
\(\Rightarrow\) 4t - 3 - 3t - 1= 5t - 4 \(\Rightarrow\) t - 4 = 5t - 4
\(\Rightarrow\) t - 5t =-4 +4 -4t = 0 \(\Rightarrow\) t = 0
21.
( )
\(\because\) (p x 14) - 19 =21 \(\Rightarrow\)149 -19 = 21
14p = 40 \(\Rightarrow\) p=\(\frac { 40 }{ 14 } =\frac { 20 }{ 7 } =2\frac { 6 }{ 7 } \)
22.
( )
Sign
23.
( )
Highest
24.
( )
x = -39
25.
( )
\(x={27\over 10}\)
26.
( )
1
27.
( )
\(\frac { Q2x+5 }{ 3.5x-3 } =\frac { 2 }{ 5 } \)
28.
( )
5(x-1)-2(x+ 8)=0
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