Latisha wants to get at least a B+ in her history class. To do so, she needs to have an overall average of at least 86%. So far, she has taken three tests and has gotten scores of 90%, 82%, and 81%. a. Use the 5-D Process to help Latisha determine what percent score she needs on the fourth test to get the overall grade that she wants. The fourth test is the last test of the grading period. b. The teacher decided to make the last test worth twice as much a regular test. How does this change the score that Latisha needs on the last test to get an overall average of 86%? Support your answer with mathematical work.