Number of hours Tap A requires to fill an empty tank : 8 hours
Number of hours Tap B requires to empty the full tank : 16 hours
Amount of water filled by Tap A in empty tank in one hour: \(\frac{1}{8}\)
Amount of water Tap B empties in one hour: \(\frac{1}{16}\)
Amount of water filled by Tap A and Tap B together in one hour: \(\frac{1}{8}-\frac{1}{16}=\frac{1}{16}\)
∴ They can fill the tank together in 16 hours.