Question

A box contains 420 coins in rupee, 50 paise and 20 paise coins , the ratio of the rupee values being 13:11:7. the number of 50 paisa coins is

Answer 1

Generally ratio of coins is given we multiply this with the denomination and get value but in this case we have value(in rs) so we divide with rupees(denomination) nd get no of coins....
Check this attachment :-)

Answer 2

let the no.of 50 paise, 20 paise and one rupee coins be 13x,11x and 7x . 420=1(13x)+0.5(11x)+0.20(7x)=> 420 =13x+5.5x+1.4x => 420=19.9x => x=4200/199 =21.15 approximately .So not possible. Hope you understood the solution .