t = int(input())
def solve():
    A, B, C, X, Y, D = map(int, input().split())
    if D <= X:
        print(A)
    elif D <= X + Y:
        dist1 = (D + X - 1) // X * A
        dist2 = D // X * A + D % X * B
        ans = min(dist1, dist2)
        print(ans)
    else:
        dist1 = (D + X - 1) // X * A
        dist2 = D // X * A + (D % X * B if D % X <= Y else B * Y + (D % X - Y) * C)
        costAB = D // (X + Y) * (A + Y * B)
        modAB = D % (X + Y)
        cntB = D // (X + Y ) * Y
        dist3 = costAB + (A - min(cntB, X - modAB) * B if modAB <= X else A + (modAB - X) * B)
        dist4 = A + Y * B + (D - X - Y) * (C - B)
        dist5 = costAB + modAB * C
        ans = min(dist1, dist2, dist3, dist4, dist5)
        print(ans)
for _ in range(t):
    solve()