#include <stdio.h>
#include <string.h>
#include <math.h>

int main(void)
{
    int num;
    int M;
    double D;
    double price;
    double chang, ujong;
    int len;
    int i;
    char s[101];
    char *Str = s;

    scanf("%d", &num);
    while (num-->0)
    {
        scanf ("%d %lf", &M, &D);
        scanf ("%s", Str);

        // printf ("Input: %d, %lf, %s\n", M, D, Str);
        len = strlen(Str);
        chang = 0;
        ujong = 0;

        for (i=(len-1);i>=0;i--)
        {
            price = 10000*pow((100-D)/100,i);
            //printf ("%lf\n", price);

            if (Str[i]=='C')
            {
                chang = (M*price)-ujong;
            }
            else if (Str[i]=='U')
            {
                ujong = (M*price)-chang;
            }
        }
        printf ("%.1lf\n", chang);
    }

    return 0;
}