def calc(a, b, c, x, d):
    p = d // x
    q = d % x
    if q <= y:
        s = q * b
    else:
        s = y * b + (q - y) * c
    return p * a + min(s, a)

def zhk():
    global a, b, c, x, y, d
    a, b, c, x, y, d = map(int, input().split())
    
    if d <= x:
        print(a)
        return
    
    ans = calc(a, b, c, x, d)
    
    if d <= x + y:
        print(min(ans, a + (d - x) * b))
        return
    
    p = d // (x + y)
    q = d % (x + y)

    if q <= x:
        q += x
        q -= y
        s = a
        s -= y * b
        if q > 0:
            s += q * b
    else:
        s = a + (q - x) * b

    ans = min(ans, p * (a + y * b) + min(calc(a, b, c, x, q), min(s, q * c)))
    ans = min(ans, a + y * b + (d - x - y) * c)
    
    print(ans)

def main():
    _ = int(input())
    for _ in range(_):
        zhk()

if __name__ == "__main__":
    a, b, c, x, y, d = 0, 0, 0, 0, 0, 0  # Initialize global variables
    main()