import sys,time

from itertools import permutations
from heapq import heappop,heappush
from collections import deque
import random
import bisect
from math import log,gcd

input = lambda :sys.stdin.readline().rstrip()
mi = lambda :map(int,input().split())
li = lambda :list(mi())

def solve(A,B,C,X,Y,D):
    """
    全部Aで済ませる
    """
    res = (D+X-1)//X * A

    """
    A,Bで済ませる
    """
    lower = max(1,(D+X+Y-1)//(X+Y))
    upper = D//X
    for k in (lower,upper):
        tmp_cost = k * A + B * (D - k * X)
        res = min(res,tmp_cost)

    """
    (X+Y)m フルに使う
    """
    k_max = D//(X+Y)
    for k in (1,k_max):
        if 1 <= k <= k_max:
            tmp_cost = k * (A+B*Y) + C * (D-k*(X+Y))
            res = min(res,tmp_cost)

    """
    Xmだけ走って最後だけ全部使う
    """
    k_max = (D-Y-X)//X
    for k in (0,k_max):
        if 0 <= k <= k_max:
            tmp_cost = (k+1) * A + B*Y + C * (D-k*X-X-Y)
            res = min(res,tmp_cost)

    
    
    return res

for _ in range(int(input())):
    A,B,C,X,Y,D = mi()
    print(solve(A,B,C,X,Y,D))