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.'

If two fifty-foot ropes are suspended from a forty-foot ceiling that is twenty feet apart, how much rope will you be able to steal if you have a knife?

In front of you, there are 9 coins. They all look absolutely identical, but one of the coins is fake. However, you know that the fake coin is lighter than the rest, and in front of you is a balance scale. What is the least number of weightings you can use to find the counterfeit coin?

Pronounced as one letter,
And written with three,
Two letters there are,
And two only in me.
I am double, I am single,
I am black blue and grey,
I am read from both ends,
And the same either way.

What comes
Once in a Year
Twice in a Month
4 times in a Week
6 times in a Day

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

What is the next number in the series?

15 29 56 108 208 ?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

What four weights can be used to balance from 1 to 30 pounds?

How many letters are in the alphabet?