Question

The S.P. of 15 articles is equal to the C.P. of 12 articles.Find gain or loss as percent

Answer 1

sp×15=cp×12
sp/cp=4/5
1/5×100
loss 20%

Answer 2

Let we assume, you purchased 12 articles in 100 and for 100 you sold 15
means you are in loss
now
loss of 3 Article on 15
3/15=1/5
1\5×100=20%