Find the original cost of order?

Question

How can i find the original cost of an order?

For example,

If the store I go to offers a 15% discount on all order but I purchase $272 of stuff after the discount, how can I found out what my original cost would be before/without the discount?

Answer 1

I think the best way to do these problems is to think of percentage change as multiplication. In this case $$ 0.85 \times \text{ original cost} = \$272 $$ so $$ \text{ original cost} = \frac{\$272}{0.85} = \cdots . $$ What you can't do is just add $15\%$ of $\$272$ to $\$272$ .