Numerical answer type, tolerance 0.5.
Answer: 4
The ketone is hexan-3-one. Enolisation toward the ethyl side gives CH3CH=C(OH)CH2CH2CH3 (E and Z), and toward the propyl side gives CH3CH2C(OH)=CHCH2CH3 (E and Z). Each double bond has different substituents on both carbons, so each is E/Z. Total = 2 + 2 = 4.