import java.io.*;
import java.math.*;
import java.lang.*;

public class ame {
	public static void main(String args[]) {
		try { new ame(); } catch (Exception e) {e.printStackTrace();}
	}
		
	public ame() throws Exception {
		BufferedReader br = new BufferedReader(new FileReader(new File("ame.in")));
		int dataSets = Integer.parseInt(br.readLine());
		
		// up to 30 stages
		float m[] = new float[30];
		float t[] = new float[30];
		float F[] = new float[30];
		
		//int n[] = new int[10000];
		
		//int total = 0;
		
		for(int dataSet = 0; dataSet < dataSets; dataSet++)
		{
			
			System.out.println("Data Set " + (dataSet + 1) + ":");
			//total = 0;
			
			String nums[] = br.readLine().split(" ");
			
			//total weight
			float weight = Float.parseFloat(nums[1]);
			
			//get all stages
			for(int a = 0; a < Integer.parseInt(nums[0]); a++) {
				//float thism;
				//float thist;
				//float thisF;
				String stage[] = br.readLine().split(" ");
				
				m[a] = Float.parseFloat(stage[0]);
				t[a] = Float.parseFloat(stage[1]);
				F[a] = Float.parseFloat(stage[2]);
				
				//System.out.println("read F " + F[a]);
				
				weight += m[a];
			}
			
			//System.out.println("weight0 " + weight);
			
			float v = 0;
			float h = 0;
			
			final float g = 9.81f;
		
			for(int c = 0; c < Integer.parseInt(nums[0]); c++) {
				float thisa;
				//System.out.println("dividing F " + F[c] + " / " + weight);
				//thisa = (F[c] - g) / weight;
				thisa = F[c] / weight;
				
				//System.out.println("accelerating(ps) at " + thisa);
				thisa = thisa - g; // subtract effect of earth's gravity downward
				
				//System.out.println("accelerating at " + thisa);
				//System.out.println("t[c] " + t[c]);
				//System.out.println("v " + v + " , a " + thisa);
				
				h += v * t[c] + 0.5f * thisa * t[c] * t[c];
				//System.out.println("h = " + h);
				v += thisa * t[c];
				
				weight -= m[c];
			}
			
		
			System.out.println((new java.text.DecimalFormat("#.##")).format(h));
		}
	}
	
}