Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

Can you solve this tricky maths equation problem by replacing it? mark with the correct symbol?

19834 -----: 187
15921 -----: 153
17561 -----: 139
13734 -----: ???

Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, "Why are you smiling?"

How did he know his companion was smiling?

They came out at night, without being called.
They lost at day, without being stolen.
Who are they?

A girl rode into a tourist spot out of the city on Thursday. She loved the place and decided to stay for a few days. She stayed for four days and then she left for back home on Thursday.

How can this be possible?

If it took eight men ten hours to build a wall, how long would it take four men to build it?

He does not have any heart but still, He manages to live.
If you kill him, you will eventually die but yet you kill him.
He cannot run, who is He?

You walk into a room that contains a match, a kerosene lamp, a candle and a fireplace. What would you light first?

I was speeding and ran through a stop sign, yet two traffic officers who were there do nothing about it.

why?

Can you place three balls such that the equation shown in the picture holds true?