Step 1: Identify the reaction type. An alkyl halide treated with alcoholic KOH undergoes elimination (dehydrohalogenation) by the E2 path, removing H and the halogen to make an alkene. Step 2: Decide which alkene is the major product. By Saytzeff's rule, the major alkene is the more substituted one, since more highly substituted double bonds are more stable. So we form the most substituted alkene the skeleton allows. Step 3: Understand alpha hydrogens for this count. For the product alkene, the alpha hydrogens are the ones on the carbons directly attached to the doubly bonded carbons, since those are the hydrogens adjacent to the double bond. Step 4: Account for the substituent carbons. The most substituted alkene from the given skeleton carries methyl and other alkyl groups on the carbons next to the double bond, and we sum all the hydrogens sitting on those neighbouring carbons. Step 5: Add up the hydrogens. Counting the hydrogens on all carbons adjacent to the double bond of the major (Saytzeff) product gives a total of $7$. Step 6: Conclude. The number of alpha hydrogens in the major product X is $7$. \[ \boxed{7} \]
