RTOS/TM4C1294NCPDT: ADC12 Clock Rate

Tool/software: TI-RTOS

I have reviewed the datasheet and documentation but struggled to find simple question: Based on setting I used, what is actual sample rate?

.....in TM4C_System_Main_PreBIOS

uINT32 ui32SysClock = SysCtlClockFreqSet((SYSCTL_XTAL_16MHZ | SYSCTL_OSC_MAIN | SYSCTL_USE_PLL | SYSCTL_CFG_VCO_480), 120000000);

....in TM4C_ADC12.c

//---------------------------------------------------Set ADC Clock 
//ADCClockConfigSet(ADC0_BASE, ADC_CLOCK_SRC_PIOSC | ADC_CLOCK_RATE_FULL, 1); //1MSPS
ADCClockConfigSet(ADC0_BASE, ADC_CLOCK_SRC_PLL | ADC_CLOCK_RATE_FULL, 30);

ADCHardwareOversampleConfigure(ADC0_BASE,16);

I have 6 channel ADC12 configured tied to HWI interface which transfer FIFO data into buffer and then post semaphore to display result, all of these are working fine. It is trigger on demand rather than driven by 

(1) Can you show me how to calculate the sample rate of the above setup or how long it takes before it finishes capture and invokes interrupts

(2) My guess it is connected to 120MHz clock source (from 16MHz XTAL).