Question

a person buys an article of rupees 20000 and sells the same for 30000 less 20% discount find his gain%

Answer 1

$Cost \:price \: of \:an \: article (c.p) = Rs\:20000$

$Discount (d) = 20\%$

$Let \: gain= g\%$

/* According to the problem given */

$s.p \times \Big( \frac{100-d}{100} \Big) = c.p\Big(100+g}{100}\Big)$

$\implies 30000 \times \Big( \frac{100-20}{100} \Big) = 20000\Big(100+g}{100}\Big)$

$\implies 30000 \times \Big( \frac{80}{100} \Big) = 20000\Big(100+g}{100}\Big)$

$\implies 30000 \times \frac{80}{100} \frac{100}{20000 }=100+g$

$\implies 120 = 100 + g$

$\implies 120 - 100 = g$

$\implies g = 20\%$

Therefore.,

$\red { Gain } \green {= 20\% }$

•••♪

Answer 2

Cost Price(C.P)=20000

Selling Price(S.P)=30000 at 20% discount

first we calculate discount

      30000×20/100=6000

30000-6000=24000

Now,

      Profit=S.P-C.P

               24000-20000

               =4000

     Profit%=Profit/C.P×100

                4000/20000×100

               ANS. 20%