What is the value of x?

Please help I am terrible at math and just trying to pass!

At the olympic games, many events have several rounds of competition. one of these events is the men's 100-meter backstroke. the upper dot plot shows the times (in seconds) of the top 8 finishers in the final round of the 2012 olympics. the lower dot plot shows the times of the same 8 swimmers, but in the semifinal round. which pieces of information can be gathered from these dot plots? (remember that lower swim times are faster.) choose all answers that apply: a: the swimmers had faster times on average in the final round. b: the times in the final round vary noticeably more than the times in the semifinal round. c: none of the above.

What is the common difference for this arithmetic sequence? -6,-2,2,6,10 a.4 b.5 c.3 d.6

Abook store is having a 30 perscent off sale. diary of the wimpy kid books are now 6.30 dollars each what was the original price of the books