Solution:

1st person : Colin
2nd person : Rooney

They both lied.(I said at-least)
(If only one lied they would both be boys or both be girls)

Solution:

Throw the ball straight up in the air.

Solution:

What

It stated 'WHAT' was the father's name.

Solution:

18 x 12 ÷ 2 + 3 = 111

Solution:

5625

n^1
75 * 75 = 5625 (sum of first 75 odd numbers).
50 * 50 = 2500 (sum of first 50 odd numbers).

Solution:

21, 28.

They are the numbers that either contain the digit 7 or are divisible by 7.

Solution:

A lion, king of the jungle! (the head of a Lamb, the middle of a pIg, the hind of a buffalO and the tail of a dragoN)

Solution:

Velma waits until night time and then goes through the second door.

(No sun at night)

Solution:

A mirror

Solution:

Sunday

Explanation:
71 days = 10 week + 1 day.
+1 day implies Sunday.