Section 1: Score 16/18
INCORRECT ANSWERS:
1. A school ordered 600 $ worth of light bulbs. Some of the light bulbs cost 1$ each and the others cost 2$ each. If twice as many 1$ bulbs as 2$ bulbs were ordered, how many light bulbs were ordered altogether?
Okay so i got 300$ worth of 1$ light bulbs and then 150$ worth of 2$ light bulbs and then by accident i had 150 instead of 300. This was all a careless mistake.
2. The three dimensional figure above has two parallel bases and 18 edges. Line segments are to be drawn connecting vertex V with each of the other 11 vertices's in the figure. How many of these segments will NOT lie on an edge of the figure?
I mainly didn't understand this problem because i thought that all of the segments lie on the edges. I am really confused so I put 0, but the real answer was 8.
Section 2: Score 11/16
The rest were careless mistakes besides the following two:
1. The number that results when an integer is multiplied by itself CANNOT end in which of the following digits?
*1
*4
*5
*6
*8
I immediately crossed out 1 & 4 because 1 can be multiplied by 1 to equal 1 and 2 can be multiplied by 2 to equal 4. 5, 6 and 8 cannot be multiplied by anything to equal that....
but the answer is 8?
2. In the figure above, what is the sum, in terms of n, of the degree measures of the four angles marked with arrows?
*n
*2n
*180-n
*360-n
*360-2n\
My answer was 360-2n. This was because i thought that in order to get the inside angle that wasn't defined yet, i should minus n from 180. That's what i did, and then i added 2n from the other angles and i got 180 -n +2n which brought me 180-n. Then i multiplied it by 2 and got 360-2n.
The answer was 2n?
Section 3: 15/18
One of them was a careless mistake, so i won't mention that.
1.NUMBER OF SIBLINGS PER STUDENT IN A PRESCHOOL CLASS
Number of Siblings: | Number of students
0 | 3
1 | 6
2 | 2
3 | 1
The table above shows how many students in a class of 12 preschoolers had 0 1 2 or 3 siblings. Later, a new student joined the class and the average ( arithmetic mean ) number of siblings per student became equal to the median number of siblings per student. How many siblings did the new student have?
This question just confused me. I still don't understand it.
2. h(t) = c - (d-4t)^2
At time t=0, a ball was thrown upward from an initial height of 6 feet. Until the ball hit the ground, its height in feet, after t seconds was given by the function h above, in which c and d are positive constants. If the ball reached its maximum height of 106 feet at time t=2.5, what was the height, in feet, of the ball at time t=1?
This is how i went about the problem:
106=c-(d-4t)^2
106=c-(d-10)^2
106=c-(d^2-20d+100)
106=c-d^2+20d-100
206=c-d^2+20d
Since i have two variables, i realized there must be a problem in the way i set this up
1 comment:
Opal,
Thanks for the posting.
1. Don't worry about the careless mistake. Stop making them.
2. on word problems, ALWAYS ALWAYS stop to check what the problem is testing. Here, its asking how many of these supposed "lines" will be on an EDGE of the figure.
The edges are all of the lines on the outside of the figure.
There are 11 possible lines, right? connecting the vertex to all of the other 11 points. Of those 11, only 3 will lie on an edge-- the 2 lines that connect the vertex to the lines on the top hexagon right next to it, and then the line that connects the vertex to the
In the shape, there are only 3 edges that have the vertex as an endpoint. Those are the 3 "lines". The other 8 "lines" go through the middle of the shape.
2) opal,
5x5=25
6x6=36
8 doesn't work.
3) Opal,
The inside angle is 180-N, right? For both the triangles?
So for 1 triangle, the sum of the other two angles add up to 180- the inside angle
180-(180-n) = N
And there are two of them. 2N. This is simple geometry supplements and triangles. You should not be getting this wrong.
In such situations, ALWAYS write what the angles are in the diagram.
"My answer was 360-2n. This was because i thought that in order to get the inside angle that wasn't defined yet, i should minus n from 180. That's what i did, and then i added 2n from the other angles and i got 180 -n +2n which brought me 180-n. Then i multiplied it by 2 and got 360-2n. "
A) this math is wrong for multiple reasons: 180-N+2N= 180+N, not 180-N
B) Also, you're not doing the problem the right way.
All you need to know are the rules of angle totals in triangles (sum of angles in a triangle=180) and the rule of supplementary angles (supplementary angles add up to 180). I don't have a problem with you getting them wrong; I do have a problem with you not being able to figure out why you got the problem wrong without me pointing it out. You should know this-- do your own diagnosis and troubleshooting, ok?
Next question, about the students.
- First question: can you read the chart and what it says? On the left side is a category showing how many siblings someone has. Categories are from 0 siblings to 4 siblings. On the left are how many people fall into that category
First thing you need to be able to do is calculate average and median # of siblings per student. Do you know how to do that?
3. You solved for the first set of values, so good: those values were h(t)=106, t=2.5
You didn't realize that in the very beginning of the problem, they gave you a set of values already. h(t)=6, t=0.
With that, you can solve the equation.
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