The answer would be the last option. :)
9514 1404 393
Answer:
Step-by-step explanation:
Generally, the single variable on the left side of the equation is the "output" or dependent variable, while any other variables on the right side of the equation are considered to be independent variables, or "input."
So, we assume your first question is asking for the value of t that makes w=176. Put the values in the equation and solve for the unknown.
w = 112 +8t
176 = 112 + 8t
64 = 8t . . . . . . . subtract 112
8 = t . . . . . . . . . divide by 8
The input for an output of 176 is 8.
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Ordered pairs are always written as ...
(input, output)
So, (4, 144) means the output is 144 for an input of 4.
85 comes immediately before
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