A wizard prepares a magic potion by mixing two key ingredients.<br>For every 10 $$ml$$ of snake's blood, he needs 25 $$ml$$ of bat's saliva. <hr> If he wants to make 420 $$ml$$ of magic potion, how much snake's blood must he have? <br> <input min="0" type="number" id ="imp6pg083q5c_1" class="lineinput" placeholder="?" />