<p>BEES question:</p>
<p>a function of bees b(t) is defined by t^2 - 20t + k for 0 <= t <= 99, where t is the day given and b(t) is the total number of bees. what day will have the same amount of bees as day 10?</p>
<p>(something along those lines)</p>
<p>answer choices, 20, 30, 40, 50, 60.</p>
<p>I can't figure it out. Help please?</p>
<p>Think symmetry of parabola. What's the vertex x-coord.?</p>
<p>are you sure this question is typed right?</p>
<p>to find the x-coord of the vertex you use -b/2a, which in this case would be 10. That means that (10,y) is the vertex, but how can some other day have the same number of Bees if there can only be one vertex?</p>
<p>Something is majorly flawed in this question...</p>
<p>Even the graphing calculator believes all values of b(t) are different. [url="<a href="http://www.algebrahelp.com/calculators/function/graphing/calc.do;jsessionid=6CE2B297305FA34C8E64143662795F5C?function%5B0%5D=(x%5E2)+-+(20*x)&function%5B1%5D=&function%5B2%5D=&function%5B3%5D=&startX=0&endX=99&scaleX=10&startY=0&endY=2000&scaleY=50&grid=true&labels=true&showWork=true&imageWidth=300&imageHeight=300&pointsX=&format=png%22%5DLook%5B/url">http://www.algebrahelp.com/calculators/function/graphing/calc.do;jsessionid=6CE2B297305FA34C8E64143662795F5C?function[0]=(x^2)+-+(20*x)&function[1]=&function[2]=&function[3]=&startX=0&endX=99&scaleX=10&startY=0&endY=2000&scaleY=50&grid=true&labels=true&showWork=true&imageWidth=300&imageHeight=300&pointsX=&format=png"]Look[/url</a>].</p>
<p>Yes, I removed the k... but K is just a constant that alters the positioning of the graph in the y-axis. It makes little difference.</p>
<p>i just did this like 3 days ago, heres my hint, ignore the K, and its a parabola, like gcf said, symmetry...reflection
dun dun dun.</p>
<p>That's what I said in my above post. Thing is, the reflection of the parabola IS NOT included in the range specified.</p>
<p>The graph is just like a one sided curve in the range given.</p>
<p>hm i dont really understand what u mean by the reflection is not included. i think it is in the range. find out the Y value . theres 2 value for 1 Y, so find that other corresponding Y, it is in the range. maybe i misunderstood something?
its not one side, its a normal parabola...</p>
<p>a function of bees b(t) is defined by t^2 - 20t + k for 0 <= t <= 99, where t is the day given and b(t) is the total number of bees. what day will have the same amount of bees as day 10?</p>
<p>Just use t = 10, find b(10), then find another value of t.
b(10) = 100 - 200 + k = k - 100
so we need t^2 - 20t = -100
t^2 - 20t + 100 = 0
However this is a perfect square whose both roots are 10.... So your values are flawed... otherwise if you had the correct values, you just had to solve this equation and you'd get 2 roots, one would be the one given in the question, and the other would be the answer.</p>
<p>
[quote]
answer choices, 20, 30, 40, 50, 60.
[/quote]
</p>
<p>I mean the reflection of t=10 is not in any of the above options.</p>
<p>ren and gcf.....can you please publish the full method?</p>
<p>The function really was: b(t) = 0.5 * t^2 - 20t + k ...</p>
<p>Hint: you want b(t) = b(10) ... solve for t</p>
<p>hell yeah....now i can solve it...............thnx fignewton....bye the way,in which section did this que appear? let me know please....</p>
<p>^It was #16 on the MC section with 16 Qs.</p>
<p>So what's the ANSWER?</p>
<p>yeah, OP copied the Q wrong, it's actually like Fignewton said,
f(t)=.5t^2-20t
plug into calc, 2 X has the same Y</p>
<p>The answer is 30.</p>
<p>Can somebody show me how they would go about olving this without calc. I did that but K was -150. so .5t^2-20t= 150, but when t=30(the answer) , its equal to -150, not 150. What did i do wrong?</p>
<p>b(t) = .5t^2 - 20t
b(10) = -150</p>
<p>b(t) = .5t^2 - 20t = -150
.5t^2 - 20t + 150 = 0
.5(t-30)(t-10) = 0
t = 10 or t = 30</p>
<p>The answer is 30.</p>
<p>actually u dont have to solve for K, if u picture the graph, imagine the K, move the graph up and down, u can see the X is not moving, Y is useless, we dont care the Y value, all we need is the reflection of X on the other side of the sym axis.</p>
<p>Very clear steps kho, thanks for that. Rn that sounds good, can you explain how you immediately recognized the answer ? I'm not following "All we need is the reflection of x". Thanks</p>