First four exams scores were 78%, 76%, 82% and 84%. What is needed on the final exam to receive a 90

First four exams scores were 78%, 76%, 82% and 84%. What is needed on the final exam to receive a 90% exam average?

We need a missing average. Using our missing average calculator with our 4 test scores and a target average of 90%, we get:
130%