import math

q = int(input())
for _ in range(q):
    a, b, c = map(int, input().split())
    if c == 1:
        print(a*b)
        continue
    num = []
    while True:
        a, mod = divmod(a, c)
        num.append(mod)
        if a == 0:
            break
    num.reverse()
    i = 0
    ans = 0
    while True:
        if num[i] == 0:
            if i < len(num) - 1:
                ans += b
            else:
                break
            i += 1
        else:
            if i == len(num) - 1:
                ans += b
                break
            else:
                if num[i+1] != 0:
                    if (num[i]*c+num[i+1]-1)//(c-1)+1 <= 2:
                        ans += 2*b
                        i += 2
                        if i == len(num):
                            break
                        else:
                            ans += b
                    else:
                        ans += 2*b
                        i += 1
                else:
                    ans += 2 * b
                    i += 1
    print(ans)