If two students, Mark and Lisa, interchange their seats and Mark's new rank from the top becomes 10th, while Lisa's rank from the bottom is now 5th, how many students are there in total?

B. 15

In a race of 15 runners, if Mark is ranked 8th from the top and then swaps positions with the runner ranked 10th, what will be Mark's new rank from the top?

C. 9TH

In a class of 30 students, John is ranked 12th from the top. What is his rank from the bottom?

B. 19TH

Alice is ranked 15th from the bottom in a group of 40 people. If she swaps ranks with Bob, who is ranked 10th from the top, what will be Alice's new rank from the top?

C. 25TH

In the sequence 5, 10, 15, 20, 25, 30, how many times does the number 15 occur?

A. 1