Question 1096528
<br>According to the wording of the problem as you show it, your answer is right.<br>
"A 70% markup on the selling price brought the selling price to $1400"<br>
That wording clearly says that the selling price was $1400 AFTER the 70% markup.  But it is also confusing because, as you say, it seems wrong to say that the selling price, plus some markup, equals the selling price.<br>
So perhaps the wording of the problem is incorrect; and perhaps your teacher was working a different problem.