user: Question: Type of Primary, and a Call letters of KKTX-FM has what average Frequency (MHz)?
Columns: ['Frequency (MHz)', 'Call letters', 'Licensed location', 'Type', 'Format']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [88.7, 'KZLO', 'Kilgore', 'Translator of K-LOVE', 'Contemporary Christian']
SQL:

assistant: SELECT AVG("Frequency (MHz)") FROM "Table" WHERE "Type" = 'Primary' AND "Call letters" = 'KKTX-FM';