main.scala

import java.io.{FileOutputStream, FileInputStream}

import scala.io.StdIn

object Main extends App {
  Console.setIn(new FileInputStream("sample.in"))
  Console.setOut(new FileOutputStream("sample.out"))

  def solve(n:Int, p:Int, q:Int, r:Int, s:Int) : Double = {
    val t = (0 until n).map(i => ((i * p + q) % r) + s).toList
    val result = (0 to n).flatMap(x => {
      val (t1, remain) = t.splitAt(x)
      (0 to remain.length).map(x => {
        val (t2, t3) = remain.splitAt(x)
        List(t1.sum, t2.sum, t3.sum).sorted.init.sum
      })
    }).toList.max.toDouble / t.sum

    result
  }

  val cases = StdIn.readLine().toInt
  (1 to cases) foreach {caseN =>
    val Array(n, p, q, r, s) = StdIn.readLine().split(" ").map(_.toInt)
    println(s"Case #$caseN: ${"%.10f".format(solve(n, p, q, r, s))}")
  }

  val cases = StdIn.readLine().toInt
  (1 to cases) foreach {caseN =>
    val Array(n, p, q, r, s) = StdIn.readLine().split(" ").map(_.toInt)
    println(s"Case #$caseN: ${"%.10f".format(solve(n, p, q, r, s))}")
  }
}