Question

cp of 6 watches is equal to sp of 4 watches find the gain percent

Answer 1

gain percent=(6/4 -1)* 100%
                    =(6/4 -4/4)*100%
                    =(2/4)* 100%
                    =50%

The input of 6 and 4 is obviously the number of watches. This formula is always useful. Hope this helps you!! :)