Answer:
1/4 or 0.25
Explanation:
1)January
2)February
3)March
4)April
5)May
6)June
7)July
8)August
9)September
10)November
11)October
12)December
Months that have less than five letters in its name
June
July
May
Probability= successful outcome ÷ possible outcone
Successful outcome=3
Possible outcome=12
Probability of Hannah guessing her brother's birthday=3÷12=1/4