One of the numbers are negative
Remember this... a negative divided by a positive will result in a negative and a negative divided by a negative will result in a positive, the same goes for multiplication
So you know the merchant made a 15% profit on the pen, so she bought it for a cheaper price. To find the cost of the pen before you have to take the price now, $6.90 and times it by 85%. You do 85% because you subtract the 15% she saved from 100% and you get 85%. So 6.90x.85= 5.865 which rounds to $5.87
One battery costs $1.44.
The unit rate would be

To get that answer, you would have to divide 13 ÷ 9.
I'm not sure if this is what you were looking for, but if it was, I hope I helped! :-)
In order to find a fraction, We know that a percentage is out of a 100. This means we can now place our fraction as:
38/100
In order to find the actual fraction, we will want to simplify. Lets find our least common factor and work down from there. Since we know that 2 can go into both of them, lets reduce by 2.
This means our fraction will now look like:
19/50
Since 19 is a prime number and cannot be divided by anything but 1 and itself, we know that this is our simplified form.
This means:
19/50 is the fraction equivalent to 38%.
High school math classes are more advanced than middle school math classes