A pair of articles was bought for Rs. 37.40 at a discount of 15%. What must be the marked price of each of the articles ?

Answer: Option C

Explanation:

We need to get the Total selling price to solve this question. Because after getting selling price we can get profit or loss, then we can calculate profit% or loss%

So lets solve this:

Price Received by selling one fourth of the material at a loss of 20% =
(1/4) * 600 * (80/100) = Rs. 120

Price Received by remaining material at a gain of 10% =
(3/4) * 600 * (110/100) = Rs. 495 [Note: 1-(1/4) = 3/4]

Total Selling Price = 120 + 465 = Rs. 615

Profit = 615 - 600 = 15

\begin{aligned}
Profit\% = \left( \frac{Gain}{Cost} * 100 \right)\% \\
= \left( \frac{15}{600} * 100 \right)\% \\
= \frac{5}{2}\% = 2\frac{1}{2}\%
\end{aligned}

Answer: Option C

Explanation:

As question states that rate was of pair of articles,

So rate of One article = 37.40/2 = Rs. 18.70

Let Marked price = Rs X
then 85% of X = 18.70

=> X = 1870/85 = 22

Answer: Option A

Explanation:

This type of question can be easily and quickly solved as following:

Let at Rs x it can earn 15% pr0fit
85:18700 = 115:x [as, loss = 100 -15, Profit = 100 +15]

x = (18700*115)/85
= Rs.25300

Answer: Option C

Explanation:

So before solving this question we will get the C.P. and S.P. of 1 article to get the gain percent.

C.P. of 1 orange = 350/100 = Rs 3.50
S.P. of one orange = 48/12 = Rs 4 [note: divided by 12 as 1 dozen contains 12 items]
Gain = 4 - 3.50 = Rs 0.50
\begin{aligned}
Gain\% = \frac{0.50}{3.50}*100 \\
= \frac{100}{7}\%
= 14\frac{2}{7}\%
\end{aligned}

Answer: Option D

Explanation:

In this type of question, we will first find total C.P. of items, then total S.P. of items, then we will get gain or loss. From which we can easily calculate its percentage.

So lets solve it now.
\begin{aligned}
\text{So, C.P. of 1st transistor = }\\
\left( \frac{100}{120} * 840 \right) = 700 \\

\text{C.P. of 2nd transistor = }\\
\left( \frac{100}{96} * 960 \right) = 1000 \\

\text{Total C.P. = 1700 }\\
\text{Total S.P. = 1800 }\\
\text{Gain = 1800 - 1700 = 100}\\
\text{Gain% = } \left( \frac{100}{1700} * 100 \right) \\
= 5\frac{15}{17}\%
\end{aligned}