Let 
be the 20 marks of the boys, and 
be the 10 marks of the girls.
We know that the global mean was 70, meaning that
Multiplying both sides by 30 we deduce that the sum of the scores of the whole classroom is
By the same logic, we work with the marks of the boys alone: we know the average:
And we deduce the sum of the marks for the boys:
Which implies that the sum of the marks of the girls is 
And finally, the mean for the girls alone is
Answer:
3 3/4
Step-by-step explanation:
5/6 is not the definite ratio, when you take a larger sample size it could be off by a bit like 499/600 or 501/600
<h3>
Answer:</h3>
4, 8, 8
<h3>
Step-by-step explanation:</h3>
At each node, three faces meet. One is square (4 sides); the other two are octagons (8 sides). Hence the tiling can be named with three numbers: 4, 8, 8.
Answer:
8
Step-by-step explanation:
Pemdas:
4-2(-2)
4+4
8
Hope this helped!
