What does the below rebus riddle means?

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

Manish has to secure 40% marks to pass his B.tech final exams.
He got just 40 marks and failed by 40-marks.

What is the maximum marks?

Can you calculate the probability of getting a sum of six when a dice is thrown twice?

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

Using four sevens (7) and a one (1) create the number 100. Except for the five numerals, you can use the usual mathematical operations (+, -, x, :), root and brackets ()

A landlord calls both of his sons and tells them that their horses will now decide who will transfer the inheritance. He tells them to race along the land till the end and the one whose horse will be slower will win and be the heir to all the property.

Both of them keep wandering for days but to no result. Then they ask a wise man regarding it. The man advises them on the matter after which they jump on the horses and race as fast as they can till the end. Why did they do it?

What did the wise man say?

Below is the sum of symbols in each row and column in the figure. Analyzing the figure, can you find out the value of the symbols?

using four eights (8) and a one (1) and one mathematical symbol , create the number 100

There are two words one resembles the "state of rest" and the other is related to "writing/reading material".

Can you name these two words which also sound similar?