Multiple Filter Average Calculation

Hi all, 

I am trying to calculate the average based off of multiple filters, beneath are some examples of what I have been trying however when displaying on 'card' it'll display as (blank). Could someone suggest where I am going wrong or any more ideas? Any help would be appreciated, thankyou!

Measure = AVERAGEX(FILTER('Combined','Combined'[Type]={"CT - Change Request (10)", "CT - General Support (5)", "CT - New Implementation (10)", "CT - Technical Issue/Fault (10)"}),'Combined'[Response Time (Days)])

Measure = CALCULATE(AVERAGEX(FILTER('Combined','Combined'[Type]={"CT - Change Request (10)", "CT - General Support (5)", "CT - New Implementation (10)", "CT - Technical Issue/Fault (10)"}),'Combined'[Response Time (Days)]))

Measure = CALCULATE(
    AVERAGE(Combined[Response Time (Days)]),
	FILTER(Combined, Combined[Type] = "CT - Change Request (10)"),
        FILTER(Combined, Combined[Type] = "CT - General Support (5)"),
        FILTER(Combined, Combined[Type] = "CT - New Implementation (10)"),
        FILTER(Combined, Combined[Type] = "CT - Technical Issue/Fault (10)")
)

Measure = CALCULATE(
    AVERAGE(Combined[Response Time (Days)]),
    FILTER('Combined','Combined'[Type]={"CT - Change Request (10)", "CT - General 
    Support (5)", "CT - New Implementation (10)", "CT - Technical Issue/Fault (10)"})
)