Let the Cost Price (CP) = 100
Then Market Price = $\dfrac{100 \times 135}{100}$ = 135
If he wants to gain 8%, SP = $\dfrac{\left(100 + Gain\%\right)}{100} \times CP$ = $\dfrac{\left(100 + 8\right)}{100} \times 100 =$ 108
Discount % = $\dfrac{\left(135-108\right)}{135} \times 100$ = $\dfrac{2700}{135}$ = 20
CP = 80,000 + 5000 + 1000 = 86000
Profit = 25%
SP = $\dfrac{\left(100 + Gain\%\right)}{100} \times CP$ = $\dfrac{\left(100 + 25\right)}{100} \times 86000$
= $\dfrac{125}{100} \times 86000 $=$ \dfrac{5}{4} \times 86000$ = $5 \times 21500 $= 107500
If a trader professes to sell his goods at cost price, but uses false weights, then
Gain% = $\left[\dfrac{error}{true value-error}\times100\right]\%$
So here profit percentage = $\left[\dfrac{200}{\left(1000 - 200\right)} \times 100\right]\%$
= $\left[\dfrac{200}{800}\times100\right]$= 25%
Let the labeled price = $x$
SP = 704
Initial Discount = 20%
Price after initial discount = $x \times \dfrac{80}{100}$
Additional discount = 12%
Price after additional discount= $x \times \dfrac{80}{100}\times \dfrac{88}{100}$
But Price after additional discount = SP = 704
$\Rightarrow x \times \dfrac{80}{100}\times \dfrac{88}{100}$ = 704
$\Rightarrow x \times \dfrac{4}{5}\times \dfrac{22}{25} $= 704
$\Rightarrow x = 704 \times \dfrac{25}{22}\times \dfrac{5}{4} = 176 \times \dfrac{25}{22}\times 5 $
= $8 \times 25 \times 5 = 40 \times 25$ = 1000
Initial Loss% = $\dfrac{CP - 400}{CP} \times 100$
If the SP is reduced from 400 to 380, Loss% = $\dfrac{CP - 380}{CP} \times 100$
It is given that If the SP is reduced from 400 to 380, Loss% increases by 2
$\Rightarrow \dfrac{CP - 380}{CP} \times 100 - \dfrac{CP - 400}{CP} \times 100$ = 2
$\Rightarrow \left(CP - 380\right) - \left(CP - 400\right) $= $\dfrac{2 \times CP}{100}$
$\Rightarrow 20 = \dfrac{2 \times CP}{100}$
$\Rightarrow CP = \dfrac{20 \times 100}{2}$ = 1000
Let the original price = 100
Then the price at which he purchased (CP)= 90% of 100 = 90
Profit = 30%
SP = $\dfrac{\left(100 + Profit\%\right)}{100} \times CP$ =$ \dfrac{\left(100 + 30\right)}{100} \times 90$
= $\dfrac{130}{100} \times 90 $ = $13\times 9$ = 117
Required% = $\dfrac{\left(117-100\right)}{100} \times 100$ = 17%
Let C.P.= Rs. 100. Then, Profit = Rs. 320, S.P. = Rs. 420.
New C.P. = 125% of Rs. 100 = Rs. 125
New S.P. = Rs. 420.
Profit = Rs. (420 - 125) = Rs. 295.
$\therefore$ Required percentage =$ \left(\dfrac{295}{420} \times 100\right) $%=$ \dfrac{1475}{21} $% = 70% [approximately].
C.P. of 1st transistor = Rs.$ \left(\dfrac{100}{120} \times 840\right) $= Rs. 700.
C.P. of 2nd transistor = Rs.$ \left(\dfrac{100}{96} \times 960\right) $= Rs. 1000
So, total C.P. = Rs. (700 + 1000) = Rs. 1700.
Total S.P. = Rs. (840 + 960) = Rs. 1800.
$\therefore$ Gain % =$ \left(\dfrac{100}{1700} \times 100\right) $%= 5$ \dfrac{15}{17} $%
Let C.P. be Rs. $ x $.
Then,$ \dfrac{1920 - x}{x} \times 100$ =$ \dfrac{x - 1280}{x} \times 100$
$\Rightarrow$ 1920 - $ x $ = $ x $ - 1280
$\Rightarrow$ 2$ x $ = 3200
$\Rightarrow x $ = 1600
$\therefore$ Required S.P. = 125% of Rs. 1600 = Rs.$ \left(\dfrac{125}{100} \times 1600\right) $= Rs 2000.
SP = 9
Loss = 20%
CP = $\dfrac{100}{(100 - Loss\%)} \times SP$ = $\dfrac{100}{(100 - 20)} \times 9$ = $\dfrac{100}{80} \times 9 $
= $\dfrac{5}{4} \times 9$
To make a profit of 5%, SP = $\dfrac{100 + Gain\%}{100} \times CP$ =$\dfrac{\left(100 + 5\right)}{100} \times CP$
=$\dfrac{105}{100} \times \dfrac{5}{4} \times 9 $= $\dfrac{105}{100} \times \dfrac{5}{4} \times 9$ = $\dfrac{21}{20} \times \dfrac{5}{4} \times 9$ =$ \dfrac{21}{4} \times \dfrac{1}{4} \times 9 $=$ \dfrac{189}{16} $= 11.81