arithmetic - tyson bought a horse and a car ridge for rs 3000 he sold the horse at a gain of 20 and the carriage at a loss of 10 thereby gaining 2 on the whole find the cost of the horse - skillgun

Let the C.P of the horse be Rs. x, then C.P of the carriage =Rs (3000-x)
20% of x-10% of (3000-x) =2% of 3000
=> x/5-(3000-x)/10=60
=> 2x-3000+x=600=3x+3600
=> x =1200
=> hence, C.P of the horse =Rs 1200

why cant we put 120% in the place of 20% since it is a gain

Raviteja said: 2/2/2015

Hi,
120% implies the gain on the whole 3000, but in the question the 20% gain is on the sale of the horse only while a 10% loss on the ridge. So this profit and loss accumulations in overall give out a 2% gain. Hence the gain and loss are added and the minus symbol there is because of the loss (negative or minus). I guess you understood.
=> 20% of x + (-10% of{3000-x}) = 2%gain on whole.