The height of a pyramid is doubled, but its length and width are cut in half. What is true about the volume of the new pyramid?
2 answers:
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Answer:
unreadable score = 35
Step-by-step explanation:
We are trying to find the score of one exam that is no longer readable, let's give that score the name "x". we can also give the addition of the rest of 9 readable s scores the letter "R".
There are two things we know, and for which we are going to create equations containing the unknowns "x", and "R":
1) The mean score of ALL exams (including the unreadable one) is 80
so the equation to represent this statement is:
mean of ALL exams = 80
By writing the mean of ALL scores (as the total of all scores added including "x") we can re-write the equation as:
since the mean is the addition of all values divided the total number of exams.
in a similar way we can write what the mean of just the readable exams is:
(notice that this time we don't include the grade x in the addition, and we divide by 9 instead of 10 because only 9 exams are being considered for this mean.
Based on the equation above, we can find what "R" is by multiplying both sides by 9:
Therefore we can now use this value of R in the very first equation we created, and solve for "x":
Answer:
1) .
2) years
Step-by-step explanation:
Let Hanna's sister be years old.
Then Hanna will be years old.
The sum of their ages will be years.
The statement "no more than 18" means the sum of their ages is less than or equal to 18.
The required inequality is;
.
2)
The inequality we just found is
.
We simplify to get;
.
we divide both sides by to get;
.
Therefore the oldest age Hannah's sister can be is years