Question

CP of 21 articles is equal to SP of 18 articles .find gain or loss percent

Answer 1

CP of 21 articles=x
CP of 1 article=x/21

SP of 18 articles=x
SP of 1 article=x/18

since x/21 <x/18, there is a gain
gain=SP-CP
=x/18-x/21
=(7x-6x)/126
=x/126

gain%=gain/CP×100
=(x/126÷x/21)×100
=(x/126×21/x)×100
=100/6
=50/3
=16 2/3%

Answer 2

Let the CP of 1 article be x

Since CP of 21 article =SP of 18 article

CP of 21 article be = 18x

SP of 18 article =21x

Gain =21x-18x

Gain =3x

Gain % = 3x/18x × 100

Gain%=1/6×100

Gain % = 50/3%