The number of girls in a class are 7 times the number of boys, which value can never be the of total students

Answer: Option B

Explanation:

As per BODMAS rule first we will solve the terms in the bracket then other.
= 7500 + (25) = 7525

Answer: Option D

Explanation:

We know
\begin{aligned} 2ab = (a^2 + b^2) - (a - b)^2 \end{aligned}

\begin{aligned} 2pq = 29 - 9 = 20 \end{aligned}

\begin{aligned} =>pq = 10 \end{aligned}

Answer: Option A

Explanation:

Tip:
As you can see, there is bar over
\begin{aligned}
\overline{\frac{1}{4}-\frac{1}{6}}
\end{aligned}
So their sign will be changed from - to + as
\begin{aligned}
\frac{1}{4}+\frac{1}{6}
\end{aligned}

Answer: Option A

Answer: Option C

Explanation:

Let the number of buffaloes be x and the number of ducks be y
=> 4x + 2y = 2 (x + y) + 24

=> 2x = 24 => x = 12