To strike 6 times, the clock goes bong-bong-bong-bong-bong-bong Notice that there are only 5 dashes between those 6 bongs. Therefore there are only 5 time intervals between the 6 bongs. So we divide 6 seconds by 5 and get each time interval between bongs as 6÷5 or 1.2 seconds. To strike 10 times, the clock goes bong-bong-bong-bong-bong-bong-bong-bong-bong-bong Notice that there are only 9 dashes between those 10 bongs. Therefore there are only 9 time intervals between the 10 bongs. Since each time interval is 1.2 seconds, 9 of those time intervals between bongs is 9×1.2 seconds which equals 10.8 seconds. Edwin