Question

A man sold two watches for rs 240 each on one he gain 20% and on the other he lost 20% find the gain or loss percent in transaction

Answer 1

let the cost price be x Rupee's
for gain of 20%
x *120/100
for loss of 20% sp x *80/100
$x \times \frac{120}{100} = 240 \\ x = \frac{240 \times 100}{120} \\ x = 200 \\ cp \: of \: one \: watch \: is \: 200 \: rs \\ x \times \frac{80}{100} = 240 \\ x = \frac{240 \times 100}{80} \\ x = 300 \: \: cp \: of \: second \: watch \\ total \: cp \: of \: both \: watches = 300 + 200 = 500 \: rs \\ total \: sp = 240 + 240 = 480 \: rs \\ there \: is \: a \: total \: loss \: of \: 500 - 480 = 20 \: rupees \\ loss \: percentage = \frac{20}{500} \times 100 \\ = 4$%