A TV is purchased at Rs. 5000 and sold at Rs. 4000, find the lost percent.

Answer: Option C

Explanation:

Friends, we know we will need gain amount to get gain percent, right. So lets get gain first.

Let the cost price of 1 pen is Re 1
Cost of 8 pens = Rs 8
Selling price of 8 pens = 12
Gain = 12 - 8 = 4

$$\begin{aligned} Gain\% = \left( \frac{Gain}{Cost} * 100 \right)\% \\ = \left( \frac{4}{8} * 100 \right)\% = 50\% \end{aligned}$$

Answer: Option B

Explanation:

Let the cost price = Rs 100
then, Marked price = Rs 135

Required gain = 8%,
So Selling price = Rs 108
Discount = 135 - 108 = 27

Discount% = (27/135)*100 = 20%

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 A

Explanation:

Suppose he bought 5 kg and 3 kg of tea.
Cost Price = Rs. (5 x 18 + 3 x 20) = Rs. 150.
Selling price = Rs. (8 x 21) = Rs. 168.
Profit = 168 - 150 = 18

So, Profit % = (18/150) * 100 = 12%

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.

$$\begin{aligned} \text{So, C.P. of 1st transistor = }\\ \left( \frac{100}{120} * 840 \right) = 700 \\ \text{C.P. of 2nd transistor = }\\ \left( \frac{100}{96} * 960 \right) = 1000 \\ \text{Total C.P. = 1700 }\\ \text{Total S.P. = 1800 }\\ \text{Gain = 1800 - 1700 = 100}\\ \text{Gain% = } \left( \frac{100}{1700} * 100 \right) \\ = 5\frac{15}{17}\% \end{aligned}$$