your test scores are 81 and 89. WHat possible scores can you earn on your next test to have a test average between 85 and 90, inclusive?

Question

your test scores are 81 and 89. WHat possible scores can you earn on your next test to have a test average between 85 and 90, inclusive?

Answer 1

85 <= (81 + 89 +  x) / 3 <=90

 

255 <= 81 + 89 + x <=270

 

255 <= 81 + 89 + x <=270

 

174 <= 89 + x <= 189

 

85 <=  x <= 100

 

x = [85, 100]