9514 1404 393
Answer:
60
Step-by-step explanation:
Let m represent the mark Cheryn scored on her first quiz. Then her average is ...
(m +76 +89)/3 ≥ 75
m +165 ≥ 225 . . . . . . . . multiply by 3
m ≥ 60 . . . . . . . . . . . . subtract 165
Cheryn scored a minimum of 60 marks on her first quiz.
