vswr mismatch

1.network A with vswr 2.5 and network B with vswr 2,cascade them .then how to cal the cascade vswr?
2.with a matched attenuator before a load with vswr 2,then how to cal vswr reduction by the attenuator?
thank u

For nr.1 the total VSWR will be 2.8 : 1 (with condition that both networks A and B having the specified VSWR at the same frequency)

Nr.2 depends what value have the attenuator in front of the VSWR 2:1 load.
For example a 6dB attenuator it will improve the VSWR up to 1.2 : 1

Everywhere we assume 50 ohms termination.