That is to say, a * * * has passed for 24 hours, but it strikes 8 o'clock three times. We can count how many times it struck in 24 hours, but our clock is 12 hours, which means it struck twice from 1 to 12, so it is 2 * (1+2+3+4. . . + 1 1+ 12)= 156

Plus the number of knocks in half an hour in 24 hours, 24 times, 156+24= 180, and the last 8 knocks at 8 o'clock, 180+8= 188.

So a * * * will knock 188.

I hope it helps you. . . .