First, there is just shy of a 20% difference in your ages. Although 3 years is not much difference, say, for 30 year olds, it is a big difference for teenagers. The two have different experiences in life and differences in what they have had time to learn.
The second issues involves legal issues: if the two are intimate, there could be all kinds of legal woes, including the possibility of imprisonment for the 18 year old in some states.
15 out of 18 or 15/18 = 83.33%
15% of 18= 15% * 18= 0.15 * 18= 2.7
15
15*18 = 270
33 - 18 = 15
15% of 18.00= 15% * 18= 0.15 * 18= 2.70
18 percent of 15 is 2.7
15 ÷ 18 = 0.8333
15% of 120 is 18.
18 multiplied by 15 is 270
15 multiplied by 18 is 270.
It is: (15+18)+12 = 45