Leap year has 366 days = 52 weeks + 2 days.
2 favorable cases (starting on Monday/Tuesday) out of 7 possible starting days.
Starting Day Extra Days 53 Tuesdays?
Monday Mon, Tue Yes
Tuesday Tue, Wed Yes
Wednesday Wed, Thu No
Thursday Thu, Fri No
Friday Fri, Sat No
Saturday Sat, Sun No
Sunday Sun, Mon No
Probability not 53 Tuesdays =1−72=75.