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

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

A man stands on one side of a river, his dog on the other. The man calls his dog, who immediately crosses the river without getting wet and without using a bridge or a boat. How did the dog do it?

Solve the counting riddle by identifying the number of triangles in the given picture.

Can you count the number of blocks in the picture below?

A girl was sitting in her hotel room when she heard a knock on the door. She opened the door and found that a man was standing outside. The man said, "Oh! I am really sorry, I thought this was my room." He then walked through the corridor to the elevator. The girl did not know the man. She closed her door and called security asking them to apprehend the man. What made her suspicious of that man? He might have been genuinely mistaken.

What am I?

How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?

A gardener planted the Lemon trees in a mathematical ordered way (i.e. he planted a tree in rows).
He created a total of 19 rows of trees.

Note: There should be more than 2 trees to count as a row.

What is the minimum number of trees required by the gardener to have 19 rows of trees?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

What has 13 hearts but no other organs?