After the 10% discount on marked price (P), the selling price is ...
... P×(100% -10%) = 0.90P
After a markup off 35% on cost, the value is
... $70×(100% +35%) = 1.35×$70 = $94.50
The retailer wants these two values to be equal:
... 0.90P = $94.50
... P = $94.50/0.90 = $105.00 . . . . . divide by the coefficient of P
The marked price should be $105.00.
