Answer:
40$+60$=100$ spent
120$sold
90$ payed
70$ refund
120 (sold) -90 (payed) =30+70 (refund) =100$ (profit)
Explanation:
You spent 100$
And you sold and got 120 but you payed 90$ from 120$ money left is 30$
Then they refunded you (pay back the money (give you the money ))
So the money that your left with is 30$ and the refund money is 70$
So add the money that your left with is gives you 100$