Answer:
The selling price is $7
Step-by-step explanation:
Step one:
Given information
She paid $2.80 per shirt
She adds a  150% markup to the total price she paid for the shirts
Let us find 150% of $2.80
=150/100*2.8
=1.5*2.8
=$4.2
Hence the selling price is the markup price plus the cost price
=4.2+2.8
=$7
