Buses to exeter leave a bus station every 20 minutrs busses to plymouth leave the bus satation every 16 minutes a bus to eveter and a bus ro plymouth both leave the bus at 8 am when will busses to exeter and a bis to plymouth next leave the bus sata

9:20 am

Step-by-step explanation:

The cycles will coincide again at the least common multiple of the cycle times.

20 min = 4 * 5 min

16 min = 4 * 4 min

The least common multiple of these times is 4 * 4 * 5 min = 80 min. 80 minutes after 8 am is 9:20 am.

The two buses will next leave at once at 9:20 am.