The discount is 45*.2=$<<45*.2=9>>9 off each pair
So she pays 45-9= $<<45-9=36>>36 each
So it will cost 36*10=$<<36*10=360>>360 before tax
The tax will add 360*.1=$<<360*.1=36>>36
So she has to pay 360+36=$<<360+36=396>>396
#### 396