Question

A man sells two mobile phones for Rs.2185 each on one he makes a profit of 15% and on the other he incurs a loss of 5% find his gain or percent on the whole transaction

Answer 1

Given,
S.P of mobile = Rs. 2185

Case I:
S.P of one mobile = 2185
loss = 5%
$cp = \frac{100}{100 - loss} \times sp$
$cp = \frac{100}{100 - 5} \times 2185$
$cp = 2300$

Case II:
S.P = 2185
gain = 15%
$cp = \frac{100}{100 + profit\%} \times sp$
$cp = \frac{100}{100 + 15} \times 2185$
$cp = 1900$

Now,
Total S.P = 4370
Total C.P = 1900 + 2300
               = 4200

Gain = S.P - C.P
        = 4370-4200
        = 170

Gain % = gain/C.P x 100
             = 170/4200 x 100
             = 4.04 %