A shopkeeper expects a gain of 45/2 % on his C.P. If his sale was Rs. 392, then find his profit.

Answer: Option B

Explanation:

\begin{aligned}
Gain\% = \\ \left( \frac{(100 + \text{common gain}\%)^2}{100} - 100 \right)\% \\
= \left( \frac{(100 + 10)^2}{100} - 100 \right)\% \\
= \left( \frac{12100 - 10000}{100}\right)\% \\
= 21\%

\end{aligned}

Answer: Option B

Explanation:

We Know,

\begin{aligned}
S.P. = \left( \frac{100+gain\%}{100} * C.P \right)\\
=> C.P. = \frac{100}{122.50}* 392 \\
= 320 \\

Profit = 392 -320 = Rs 72
\end{aligned}

Answer: Option D

Explanation:

Here always remember, when ever x% loss,
it means S.P. = (100 - x)% of C.P
when ever x% profit,
it means S.P. = (100 + x)% of C.P

So here will be (100 - x)% of C.P.
= 80% of 1200
= 80/100 * 1200
= 960

Answer: Option C

Explanation:

Let original Cost price is x
Its Selling price = 105/100 * x = 21x/20
New Cost price = 95/100 * x = 19x/20
New Selling price = 110/100 * 19x/20 = 209x/200
[(21x/20) - (209x/200)] = 1

=> x = 200

Answer: Option D

Explanation:

Gain % = (164.36*100/2400) = 6.84 % = 7% approx