By multiplying the discounted price by the percent which is 22% or .22, and then adding it to the discounted price the regular price will be known. 42*.22=9.24+42= Regular price The regular price is $51.24
we want to find how much is 100% so we multiply 42/78 by 100/x where x is the cost since the same fraction inverted and multiplied by itself is = to 1. (if you don't get this feel free to message me)
so 4200/78x we divide this on a calculator and get $53.85