Martin's average score after 4 tests is 89. What score on the 5th test would bring Martin's average up to exactly 90?

Sam makes his sales calls according to a pattern. he travels either north or south depending on the calendar. some of his past trips were as follows: on february 17, april 24, june 10, september 19, and november 3 he drove north. on february 28, may 25, august 22, november 20, and december 18, he drove south. describe sams' pattern. in which direction will sam drive on oct4 and oct 24?

The parabola opens: y=√x-4 (principal square root) up down right left

Any is very appreciated! (picture is provided below)not sure how to do this at all won't lie