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:
2/3
Step-by-step explanation:
Divide 5/6 by 5/4
Find the Reciprocal of 5/4
5/6 times 4/5
5/3 time 2/5
10/15
2/3
4) The first and second terms for both ratios need to be in the same order.
Step-by-step explanation:
Given ratio is:
16:36
In order to find any ratio equivalent to given ratio, the ratio can be divided by a number or multiplied to a number.
The equivalent ratio that is given: 72:32
If we multiply the given ratio by 2: We get 32:72
So,
Looking at the options we can conclude that the right answer is
4) The first and second terms for both ratios need to be in the same order.
Keywords: Ratio, Fractions
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