import sys

input = sys.stdin.readline

for _ in range(int(input())):
    A, B, C, X, Y, D = map(int, input().split())
    # 全用A
    ans = ((D + X - 1) // X) * A
    # 全用A, 如果有余数用B补齐
    if D > A and D % A:
        t = (D // X) * A
        t += (D % X) * B
    # A + B, 然后全用C
    if D > X:
        if D <= X + Y:
            t = A + B * (D - X)
            if t < ans: ans = t
        else:
            t = A + B * Y + (D - X - Y) * C
            if t < ans: ans = t
    # 不断重复 A + B
    cnt = D // (X + Y)
    t = cnt * (A + B * Y)
    if D % (X + Y):
        r = D % (X + Y)
        if r <= X:
            t += A
        else:
            t += A + (r - X) * B
    if t < ans: ans = t
    ## 不断重复A + B, 但是如果有余数用C补齐
    if D > X + Y:
        cnt = D // (X + Y)
        t = cnt * (A + B * Y)
        t += (D % (X + Y)) * C
        if t < ans: ans = t
    print(ans)

answer.code:7:7: error: invalid preprocessing directive #\U00005168\U00007528A
    7 |     # 全用A
      |       ^~~~~
answer.code:9:7: error: invalid preprocessing directive #\U00005168\U00007528A
    9 |     # 全用A, 如果有余数用B补齐
      |       ^~~~~
answer.code:13:7: error: invalid preprocessing directive #A
   13 |     # A + B, 然后全用C
      |       ^
answer.code:21:7: error: invalid preprocessing directive #\U00004e0d\U000065ad\U000091cd\U0000590d
   21 |     # 不断重复 A + B
      |       ^~~~~~~~
answer.code:31:5: error: stray ‘##’ in program
   31 |     ## 不断重复A + B, 但是如果有余数用C补齐
      |     ^~
answer.code:1:1: error: ‘import’ does not name a type
    1 | import sys
      | ^~~~~~
answer.code:1:1: note: C++20 ‘import’ only available with ‘-fmodules-ts’, which is not yet enabled with ‘-std=c++20’