Which two months in a year have the same calendar?

In the series,$6, 4, 1, 2, 2, 8, 7, 4, 2, 1, 6, 3, 8, 6, 2, 1, 7, 1, 4, 1, 3, 2, 8, 6$,how many pairs of alternate numbers have a difference of $2$?

$A$ number is greater than $3$ but less than $8$. Also,it is greater than $6$ but less than $10$. The number is

Hemang is $16^{th}$ from the top and $12^{th}$ from the bottom in merit in the class. How many students are there in the class?

Sajith ranked thirteenth from the top and twenty-sixth from the bottom among those who have passed in the annual examination in a class. If six students have failed in the annual examination, what was the total number of students in that class?

In a class of $60$ students, where girls are twice the number of boys, Kamal ranked $17^{th}$ from the top. If there are $9$ girls ahead of Kamal, how many boys are after him in rank?