In your class, you have scores of $96,91,84,$ and $79$ on the first four of five tests. To get a grade of $B,$ the average of the first five tests scores must be grea than or equal to $80$ and less than $90.$

a$.$ Solve an inequality to find the least score you can get on the last test and still earn a B$.$

b$.$ What score do you need if the fifth test counts as two tests?

a$.$ The least score you need on the last test to get a B is