seller selling an apple for rs . 20 , a seller loses 1 / 6 th of what it costs him . the cp of the apple is ?
"sp = 20 loss = cp 21 loss = cp − sp = cp − 20 ⇒ cp 21 = cp − 20 ⇒ 20 cp 21 = 20 ⇒ cp 21 = 1 ⇒ cp = 21 c"
add(20, 1)