The price of an article is marked so as to gain 20%but when a 5% discount allowed in marked price there is profit of rs 4200.find the cost price of the article

30000

Explanation:

here

gain =20%

also mp is set in such a way that we will gain 20% profit so,by the question

mp=cp+20%of cp

=x(let)+20%of x

= 120/100x

also,if 5% discount is allowed on mp then rs4200 will be profit.,then we have

sp=120/100 x - 5%of 120/100 x

=120/100 x - 600/10000 x

=12000-600/10000 x

=11400/10000 x

=114/100 x

again ,

profit =sp -cp

4200=114/100 x- x

4200= 14x/100 (after taking l.c.m)

x=420000/14 (after cross multiply)

x=rs 30,000

my answer is the spanish won