What common phrase is represented by the below lines

Easy going:
Weak, 'I'm going.'
Tough, 'I'm staying.'

Medium going:
Weak, 'I'm going.'
Tough, 'I'm staying.'

Tough going:
Weak, 'I can't do it, I'm staying!'
Tough, 'Let's get going.'

What is the four-digit number in which the first digit is one-third the second, the third is the sum of the first two, and the last is three times the second?

When my father was 31 I was 8. Now he is twice as old as me. How old am I?

What does this mean?

CCCCCCC

Can you identify if it's a murder or a suicide ?

A blonde put eyeliner on her head. Why?

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?

I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?

Can you solve this amazing hard number series problem?
7, 8, 10, 12, 16, 18 ?

Samuel was out for a walk when it started to rain. He did not have an umbrella and he wasn't wearing a hat. His clothes were soaked, yet not a single hair on his head got wet. How could this happen?