15 can vary by 2%, this means that the range of values you can observe are 2% below 15 and 2% above 15.
First, you have to determine how much does the percentage represents with regards to the value of reference. To do so, you have to calculate the 2% of 15:
-Multiply 2 by 15 and divide the result by 100
[tex]\frac{2\cdot15}{100}=\frac{30}{100}=3[/tex]The 2% of 15 is 3, which means that the range of values you are looking for is 3 units below 15 and 3 units above.
The minimum value of the range: subtract 3 to 15
[tex]15-3=12[/tex]The maximum value of the range: add 3 to 15
[tex]15+3=18[/tex]The range of allowable values is [12;18]
