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.'

I’m light as a feather, yet the strongest person can’t hold me for five minutes. What am I?

Name a key which is hardest to turn.

I sleep during the day and fly at night, but I have no feathers to aid my flight. What am I?

The two towns are exactly 100 km apart. John leaves City A driving at 30 km/hr and Jacob leaves City B half an hour later driving at 60 km/hr. Who will be closer to City A when they meet?

What number comes next in this sequence:
7 8 5 5 3 4 4 _

A man looks at a painting in a museum and says, “Brothers and sisters I have none, but that man’s father is my father’s son.” Who is in the painting?

Name the three-letter word that can complete the below words?

A) L O _ _ _ E
B) E D U _ _ _ E
C) _ _ _ E R
D) _ _ _ T L E

What number do you get when you multiply all of the numbers on a telephone's number pad?

What is next number in the pattern below:

131 517 192 123 ?