Answer: Option B. -> False
:
B
An equation remains same even if the LHS and RHS are interchanged.

:
Let the present age of Kundan be $x$.
So, Karan's present age is $4x$.
After 6years,
Kundan's age = $(x+6)$
Karan's age = $(4x+6)$
Also, Karan's age would be twice of Kundan.
$\text{So, (4x +6) = 2 (x +6)}$
$\text{4x +6 = 2x +12}$
$\text{x = 3}$

Answer: Option C. -> Pandu who has weight of 20 kg 
:
C
It is given that Krishna's weight is 60 kg and Karan's weight is 80 kg. To balance the see-saw Krishna needs another person.
Let the required weight needed to balance the see-saw be $x$kg
Then, $60+x=80x=80-60=20$
So, Krishna should take help of a kid who weighs exactly 20 kg. Thus, Pandu would be the correct selection.

:
Grand daughter's age is $10$ years now. So her grandpa's age is
$8+6\times 10=8+60=68$
Grandpa is $68years$ old by $2015$. So he was born in $1947$.

Answer: Option C. -> 42
:
C
As the number of questions answered is unknown, let us assume that unknown variable as '$x$'.
If the number of questions answered correctly are x, then the number of questions answered incorrectly will be $(50-x)$.
For each correct answer, she gets $2$ marks. So the marks scored for x correctly answered questions are $2x$. Similarly, the marks deducted for (50-x) incorrectly answered questions are $(50-x)\times 1=50-x$
Now, the total marks scored by Preeti will be
$\text{2x- (50 -x) = 2x -50 +x = 3x -50}$ (For each wrong answer, one mark is deducted from the total score)
$\text{The final equation is, 3x -50 = 76}$
$\text{3x = 50 +76 = 126}$
$x=\frac{126}{3}=42$
$\text{So, the total number of questions answered correctly by Preeti are 42.}$

:
The number of chocolates Bittu has
= $5+(7\times \text{number of chocolates Kitty has)}=5+(7\times 5)$
$=40$

Answer: Option A. -> 54
:
A
Let us say 'x' is the number . Given that$50$ is subtracted from it and the result obtained is $4$.
So mathematically, $x-50=4$ is the equation.
Thus, $x=50+4=54$
$\text{54 is the number.}$

Answer: Option A. -> True
:
A
An expression having equality sign is called an equation.

Answer: Option A. -> True
:

No, because every equation must be equated with some quantities by including "=”. So, the given problem is an expression.

Answer: Option A. -> True
:

Steps: 1 Mark
Result: 1 Mark
$\frac{3x+5}{7}=\frac{16}{7}$
Or, $(3x+5)\times 7=16\times 7$
Or, $21x+35=112$
Or, $21x=112-35$
Or, $21x=77$
Or, $x=\frac{77}{21}=\frac{11}{3}$.