Answer: 0.15; 15%
Explanation:
Both decimals and percentages are easily represented in terms of 100. That is why the first step you should do is multiply the numerator and the denominator by 5 to easily do the conversions

You are allowed to do this because in math, the two things you can do to manipulate terms are add 0 and multiply by one. Since we are multiplying both the numerator and denominator by 5, it is equivalent to multiplying by one.
Now, we must convert 15/100 into a decimal. Since 100/100 is 1, 15/100 can be expressed as 0.15.
Now, we must convert 15/100 into a percent. You can either multiply the decimal amount by 100 or you can just remove the 100 in the denominator and get 15%.