Hi Kelvin,
I like your temperature scale. :-)
A car that is sold for $6000 and yields a 20% profit, means that the dealer bought the car for a lower price than $6000 and 20% of that lower price is added to it to get $6000.
A car that is sold for $6000 at a 20% loss, means that the dealer bought the car for more than $6000 and lost 20% of that higher price.
20% of a bigger number is more than 20% of a smaller number so the dealer lost money.
To figure the profit, let X = the original purchase price.
Then X + 0.2X = 6000
1.2X = 6000
X = $5000 and the dealer made a profit of $1000
To figure the loss, let X = the original purchase price
Then X - 0.2X = 6000
0.8X = 6000
X = $7500 and the dealer lost $1500
Subtracting his $1000 profit means that he had a net loss of $500.
Dan

David W.
10/16/15