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

Which of the following is the formula for the sequence graphed below

Which rational number could be graphed between -4 and -5

How many of the 250 grandparents in the population would you expect to prefer online shopping with merchant a? merchant a: 4 merchant b: 6 merchant c: 2 merchant d: 3 other: 5 none: 5 answer choices: a.about 4 b.about 8 c.about 40 d.about 21