The math teacher would be happy if the class average test score was at least 85. There are 10 students in the class, 5 of which scored a 92 on the test and 4 of which scored an 80. What would the last student have to score to at least make the teacher happy?
Thoughts? Step-by-step reasoning:
5 students scored a combined total of 92 * 5 = 460. 4 additional students scored a combined total of 80 * 4 = 320. 9 students therefore scored a combined total of 460 + 320 = 780. We know the total combined score for 10 students must be at least 85 average * 10 students = 850. Therefore, the last student must score at least an 850 - 780 = 70.
Thus, the answer is 70.