If 5 cats catch 5 mice in 5 minutes, how long will it take one cat to catch a mouse?

A man has a barrel filled with oil that weighs 100 pounds, and then he puts something into it. Now the barrel weighs less than 100 pounds. What did he put in the barrel?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who am I?

Which is Odd One Out and why?

4377

3954

9862

8454

9831

Why is the longest human nose just 11 inches?

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

Can you decipher the two rows to find the hidden word?

I am green and found in the forest and have needles instead of leaves. What am I?
Hint 1: It can be used for Christmas decorations.
Hint 2: I have a strong, scent that is used in air fresheners.

A famous swimmer can swim downstream in a lake in exactly 40 minutes with the lake current.
He can swim upstream in that lake in exactly 60 minutes against the lake current.
The length of the lake is 2 km.

How long he can cover the distance of one side at a still lake with no current?

I have nine bottles of wine and one of the nine bottles is poisoned.
I need to find the poisoned bottle with two facts
(1) Poison is deadly, only a sip will cost death
(2) I have two mice to do so.

How should I do it?