Urgent brainliest given mr brown gives his class a test. the 10 girls in the class get a mean mark of 70%.the 15 boys in the class get a mean mark of 80%.nick says that because the mean of 70 and 80 is 75 then the mean mark for the whole class in the test is 75%. nick is not correct. is the correct mean less than or greater than 75%? you must justify your answer.