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

Replace the question mark with the correct number in the below-given picture?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

2 ladies and 2 girls need to cross a river in a boat big enough for 1 LADY or 2 girls. How do they do it?

There was once a college that offered a class on probability applied to the real world. The class was relatively easy, but there was a catch. There were no homework assignments or tests, but there was a final exam that would have only one question on it. When everyone received the test paper it was a blank sheet of paper with a solitary question on it: 'What is the risk?'.Most students were able to pass, but only one student received 100% for the class! Even stranger was that he only wrote down one word!
What did he write?

If in a car race, the man who came two places in front of the last man finished one ahead of the man who came fifth, how many contestants were there?

For this puzzle, you might have to find logic in something illogical. But hey, it's fun and a healthy little break from your strenuous puzzle-solving sessions.

Can you decipher the meaning in the following cluster of letters?

ITIT,NCENTCENT

Can you name any English verb that becomes its past tense by simply rearranging the alphabets ?

Can you make a six-letter word using the letters N, A and B ?

My first is in chocolate but not in ham. My second is in cake and also in jam. My third at tea time is easily found. Altogether, this is a friend who is often around. What is it?