[填空题]
According to a rule-of-thumb, every five 73e(q,qkss cam.kmb. seconds bebsshi/kknmk8 a1w,;56 l*ja 3 ib,ctytween a lightning flash and the following thunder gives the distance to the flash in miles. Assuming that the flash of light arrives in essentiallnisbwb/k8 3;h ,6l kc*tysamka,15 jiy no time at all, estimate the speed of sound in m/s from this rule. m/s
