t = int(input())
for QT in range(t):
a, b, c, x, y, d = input().split()
a, b, c, x, y, d = int(a), int(b), int(c), int(x), int(y), int(d)
c1 = 0
c1 = (d + x - 1) // x * a
if d > x:
if d % x <= y:
c1 = min(c1, d // x * a + b * (d % x))
else:
c1 = min(c1, d // x * a + b * y + ((d % x) - y) * c)
if (d % x) // y <= d // x:
c1 = min(c1, d // x * a + b * (d % x))
else:
print(c1)
continue
if d >= x + y:
c1 = min(c1, c * d - c * x - c * y + a + b * y)
if d % (x + y) == 0:
c1 = min(c1, d // (x + y) * (a + b * y))
elif d % (x + y) <= x:
c1 = min(c1, d // (x + y) * (a + b * y) + a - b * min(d // (x + y) * y, x - d % (x + y)))
else:
c1 = min(c1, d // (x + y) * (a + b * y) + a + (d % (x + y) - x) * b)
c1 = min(c1, d // (x + y) * (a + b * y) + a * ((d%(x+y)+x-1)//x)-b*min(((d%(x+y)+x-1)//x*x+d // (x + y)*(x+y)-d),d // (x + y)*y))
if d > x + y:
c1 = min(c1, d // (x + y) * (a + b * y) + (d % (x + y)) * c)
print(c1)