Question

Mr brown gives his class a test.
The 10 girls in the class get a mean mark of 70 percent.
The 15 boys in the class get a mean mark of 80 percent.
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 percent.
Nick is not correct.
Is the correct mean mark less than or greater than 75 percent.
You must justify your answer!


Please answer question above i have no clue but as i have to show my work, here it is:

There are more girls than boys not an equal amount of girls and boys so the mean cannot be the middle number of 70 and 80.

Please answer and quickly with step by step clear help.

Answer 1

please quickly answer i need to know this quick to explain to the class

Answer 2

Isn't it 70 + 80 = 150
150 / 2 = 75 ?

Answer 3

Or maybe 70% (0.7) x 80% (0.8) = 0.56

0.56 / 2 = 0.28

So probably 28 percent?

Answer 4

any tutors out there know?

Answer 5

i mean the exact method and answer??

Answer 6

girls- 10 x 70 = 700
boys- 15 x 80 = 1200

700+1200 = 1900

1900/25 = 76%

76% is more than 75%

so the answer is more than

Answer 7

girls- 10 x 70 = 700
boys- 15 x 80 = 1200

700+1200 = 1900

1900/25 = 76%

76% is more than 75%

so the answer is more than

im not a teacher but i think this is the answer

im in year 9 by the way!

Answer 8

cheers bro