Can someone help me understand these two probability math problems?

11. a particular type of cell doubles in number every hour. which function can be used to find the number of cells present at the end of h hours if there are initially 4 of these cells? a. n = 4 ()" b. n = 4(2)" c. n = 4 + (2)" din = 4 +"

Henry is an avid reader, he devours 90 pages in half an hour how many pages has henry read per minute?

What is the 17th term in the arithmetic sequence in which a6 is 101 and a9 is 83