Ok, So i guess this is how it goes :
Lets say 1 item cost 1 buck.
Thus, buy 100 items for 90 bucks (10% purchase fraud).
Now, sell 100 items for 110 bucks (10% sale fraud).
Total money in : 90 bucks.
Total money out : 110 bucks.
Profit Percentage = $\frac{110 - 90}{90}*100$ = $22\frac{2}{9}$
Let $c$ be each lobster's cost price. Then the total revenue (= total/net selling price) from selling the $18$ lobsters is $1.5$ times their total cost price, which is $1.5(\$18c) = \$27c.$ This total revenue is made up of two parts: (i) The total revenue from selling $16$ lobsters each at a selling price of $\$1.6c,$ which is $16(\$1.6c) = \$25.6c.$ (ii) The total revenue from selling $2$ lobsters each at a selling price of $2\left(1 - \frac{r}{100}\right)(\$c),$ where $r\%$ is the percentage loss for selling each of these $2$ lobsters. Therefore, we have
$$ \$27c \;\; = \;\; \$25.6c \; + \; \$2\left(1 - \frac{r}{100}\right)c $$
Dividing both sides by $c$ and rearranging a bit (and working with pure numbers) gives
$$ 27 - 25.6 \; = \; 2 - \frac{r}{50} $$
$$ -0.6 \; = \; -\frac{r}{50} $$
$$ r \; = \; 30 $$
Therefore, the answer to (A) is $30\%.$
For (B), the total selling price is equal to $\$1755.$ Therefore, $\$27c = \$1755,$ or $c = \$65,$ and hence the loss amount for each of the $2$ remaining lobsters is $30\%$ of $\$65,$ which equals $(0.3)(\$65) = \$19.50.$
Best Answer
Call the price he paid for the shirt that gives him a 10% profit for $x$, then we have that 110% of $x$ is $880$. Correspondingly call the price of the he sold with a 20% lossfor $y$, then we have that 80% of $y$ is $880$. Written as formulas: $$ 1.1x=880 $$ and $$ 0.8y=880 $$ From that we find that $x=800$ and $y=1100$. So he spend a total of $1900$ and got a total income of 1760, so he has a total loss of $1900-1760=140$ which is $140/1900 \approx 0.0736$ or 7.36%.