a person sells an article at rs 550 ,gaining 1/10 of its cost price . find gain percent.

SP = Rs 550

Gain = 1/10 * CP

IF CP IS 100 THEN GAIN IS 10

So CP = 100/110 * 550 = 500

Gain = 550 - 500 = 50

Gain % = 50/500 * 100 = 10%