A shopkeeper sells one transistor for Rs. 840 at a gain of 20% and another for Rs. 960 at a loss of 4%. His total gain or loss percent is:
5$ \dfrac{15}{17} $% loss
5$ \dfrac{15}{17} $% gain
6$ \dfrac{2}{3} $% gain
None of these
Explanation:
C.P. of 1st transistor = Rs.$ \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} $%