import strutils, sequtils, math

proc printf(formatstr: cstring) {.header: "<stdio.h>", importc: "printf", varargs.}

# proc f(n: float64, a, b : int): float64 = pow(n, a.float64) * pow(ln(n), b.float64)
proc f(n, a, b : float64): float64 = a*log2(n) + b*log2(ln(n))

when isMainModule:
  var m = stdin.readLine.parseInt
  for i in 0..m-1:
    var
      tmp = stdin.readLine.split
      a = tmp[0].parseInt.float64
      b = tmp[1].parseInt.float64
      t = tmp[2].parseFloat
      (l, r) = (0.0, 1000000000.0)

    for i in 1..64:
      var mid = (l + r) / 2
      if f(mid, a, b) <= log2(t): l = mid
      else: r = mid

    printf("%.11f\n", r)