The cost price of 20 articles is the same as the selling price of x articles. If the profit is 25%, find out the value of x

Answer: Option D

Explanation:

Let the Cost Price of one article = Rs. 1
CP of x articles = Rs. x
CP of 20 articles = 20
Selling price of x articles = 20

Profit = 25% [Given]

\begin{aligned}
\Rightarrow \left (\dfrac{SP - CP }{CP}\right ) = \dfrac{25}{100} = \dfrac{1}{4}

& \Rightarrow \dfrac{\left(20-x \right )}{x} = \dfrac{1}{4} \\
& \Rightarrow 80 - 4x = x \\
& \Rightarrow 5x = 80 \nonumber \\
& \Rightarrow x = \dfrac{80}{5} = 16 \\

\end{aligned}

Answer: Option C

Explanation:

Let the cost price 1 article = Re 1
Cost price of x articles = x
S.P of x articles = 20

Gain = 20 -x

\begin{aligned}
=> 25 = \left( \frac{20-x}{x} * 100 \right) \\
=> 2000 - 100x = 25 x \\
=> x = 16
\end{aligned}

Answer: Option B

Explanation:

Let the C.P. = x,
Then S.P. = (120/100)x = 6x/5
New S.P. = 2(6x/5) = 12x/5

Profit = 12x/5 - x = 7x/5

Profit% = (Profit/C.P.) * 100
=> (7x/5) * (1/x) * 100 = 140 %

Answer: Option C

Explanation:

Let the new S.P. be x, then.
(100 - loss%):(1st S.P.) = (100 + gain%):(2nd S.P.)

\begin{aligned}
=>\left( \frac{95}{1140} = \frac{105}{x} \right) \\

=> x = 1260
\end{aligned}

Answer: Option C

Explanation:

From the question it is clear that, Gain is 20%
From 1, it is clear that S.P. - C.P. = 40, so it is sufficient to get answer.
While 2 is not sufficient to get answer.