#include <bits/stdc++.h>
#define int int64_t
using namespace std;

struct Big {
	int len, s[5000];
	Big() { memset(s, 0, sizeof(s)); len = 1; }
	Big(int val) { *this = val; }
	Big(const char* val) { *this = val; }
	Big operator = (int32_t  val) {
		char s[5000];
		sprintf(s, "%lld", val);
		*this = s; return *this;
	}
	Big operator = (const char* val) {
		len = strlen(val);
		while (len > 1 && val[0] == '0') ++val, len--;
		for (int i = 0; i < len; ++i) s[i] = val[len - i - 1] - '0';
		return *this;
	}
	inline void deal() {
		while (len > 1 && !s[len - 1]) len--;
	}
	Big operator + (const Big& a) const {
		Big res; res.len = 0;
		int top = max(len, a.len), add = 0;
		for (int i = 0; add || i < top; ++i) {
			int now = add;
			if (i < len) now += s[i];
			if (i < a.len) now += a.s[i];
			res.s[res.len++] = now % 10;
			add = now / 10;
		}
		return res;
	}
	Big operator - (const Big& a) const {
		Big res; res.len = 0; int del = 0;
		for (int i = 0; i < len; ++i) {
			int now = s[i] - del;
			if (i < a.len) now -= a.s[i];
			if (now >= 0) del = 0;
			else del = 1, now += 10;
			res.s[res.len++] = now;
		}
		res.deal(); return res;
	}
	Big operator * (const Big& a) const {
		Big res; res.len = len + a.len;
		for (int i = 0; i < len; ++i)
			for (int j = 0; j < a.len; ++j)
				res.s[i + j] += s[i] * a.s[j];
		for (int i = 0; i < res.len; ++i)
			res.s[i + 1] += res.s[i] / 10, res.s[i] %= 10;
		res.deal(); return res;
	}
	Big operator / (const Big& a) const {
		Big res, cur; res.len = len;
		cur = 0;
		for (int i = len - 1; ~i; --i) {
			cur = cur * 10, cur.s[0] = s[i];
			while (cur >= a)
				cur -= a, res.s[i]++;
		}
		res.deal(); return res;
	}
	Big operator % (const Big& a) const {
		Big res = *this / a;
		return *this - res * a;
	}
	Big operator += (const Big& a) { *this = *this + a; return *this; }
	Big operator -= (const Big& a) { *this = *this - a; return *this; }
	Big operator *= (const Big& a) { *this = *this * a; return *this; }
	Big operator /= (const Big& a) { *this = *this / a; return *this; }
	Big operator %= (const Big& a) { *this = *this % a; return *this; }
	bool operator < (const Big& a) const {
		if (len != a.len) return len < a.len;
		for (int i = len - 1; ~i; i--)
			if (s[i] != a.s[i]) return s[i] < a.s[i];
		return false;
	}
	bool operator >  (const Big& a) const { return a < *this; }
	bool operator <= (const Big& a) const { return !(*this > a); }
	bool operator >= (const Big& a) const { return !(*this < a); }
	bool operator == (const Big& a) const { return !(*this > a || *this < a); }
	bool operator != (const Big& a) const { return *this > a || *this < a; }
	void print() {
		for (int i = this->len - 1; ~i; --i)
			printf("%lld", this->s[i]); puts("");
	}
	void read() {
		char d[5000];
		scanf("%s", d);
		int l = strlen(d);
		for (int i = 0; i < l; i++)
			this->s[i] = d[l - i - 1] - '0';
		len = l;
	}
};

void solve(){
	Big zero;
	zero = 0;
	Big A, B, C, D, X, Y;
	A.read(); B.read(); C.read(); X.read(); Y.read(); D.read();
	if(D <= X) {
		A.print();
	}
	else if(X < D and D <= X + Y) {
		Big ans = A + B * (D - X);
		if(ans > A * (D / X + (D % X != zero))) ans = A * (D / X + (D % X != zero));
		if(ans > (D / X) * A + (D % X) * B) ans = (D / X) * A + (D % X) * B;
		ans.print();
	} else {
		Big ans = A + B * Y + C * (D - X - Y);
		Big ans1 = (D / X + (D % X != zero)) * A;
		if(ans > ans1) ans = ans1;
		if(D % X <= Y) ans1 = (D / X) * A + (D % X) * B;
		else ans1 = (D / X) * A + (D % X - Y) * C + B * Y;
		if(ans > ans1) ans = ans1;
		ans1 = (D / (X + Y)) * (A + B * Y);
		if(D % (X + Y) <= X) {
			ans1 += A;
			if((D / (X + Y)) * Y >= (X - D % (X + Y))) ans1 -= (X - D % (X + Y)) * B;
			else ans1 -= (D / (X + Y)) * Y * B;
		}
		else ans1 += A + (D % (X + Y) - X) * B;
		if(ans > ans1) ans = ans1;
		ans1 = (D / (X + Y)) * (B * Y + A) + C * (D % (X + Y));
		if(ans > ans1) ans = ans1;
		if((D / X) * Y > D % X) ans1 = A * (D / X) + Y * (D % X);
		if(ans > ans1) ans = ans1;
		ans.print();
	}
}

int32_t main()
{
	int tc;
	cin >> tc;
	while(tc--) solve();
	return 0;
}