72 is the minimum grade he must get on the last test in order to have an average of 77.
<u>Step-by-step explanation:</u>
The grades of a student are given 72,91,78,72 and the grade of his last test is not given.
- You have to find the minimum grade the student shall get, so that the student average must be 77.
- The four grades are already given. Therefore, we need to find only the fifth grade.
The term average is defined as the sum of all the data in a set divided by the number of data in a set.
Here, the number of data is 5. (Because the students has 4 grades plus one grade for his last test).
The average he should get is 77.
Average = Sum of all grades / number of grades
Let, 'x' be the grade of the last test.
⇒ 77 = (72+91+78+72+x) / 5
⇒ 77 = (313+x) / 5
⇒ 385 = 313 + x
⇒ x = 385 - 313
⇒ x = 72
The minimum grade he must get on the last test is 72.
tis a little of plain differentiation.
we know the radius of the cone is decreasing at 10 mtr/mins, or namely dr/dt = -10, decreasing, meaning is negative.
we know the volume is decreasing at a rate of 1346 mtr/mins or namely dV/dt = -1346, also negative.
so, when h = 9 and V = 307, what is dh/dt in essence.
we'll be needing the "r" value at that instant, so let's get it
now let's get the derivative of the volume of the cone
![V=\cfrac{1}{3}\pi r^2 h\implies \cfrac{dV}{dt}=\cfrac{\pi }{3}\stackrel{product~rule}{ \left[ \underset{chain~rule}{2r\cdot \cfrac{dr}{dt}}\cdot h+r^2\cdot \cfrac{dh}{dt} \right]} \\\\\\ -1346=\cfrac{\pi }{3}\left[2\sqrt{\cfrac{307}{3\pi }}(-10)(9)~~+ ~~ \cfrac{307}{3\pi } \cdot \cfrac{dh}{dt}\right]](https://tex.z-dn.net/?f=V%3D%5Ccfrac%7B1%7D%7B3%7D%5Cpi%20r%5E2%20h%5Cimplies%20%5Ccfrac%7BdV%7D%7Bdt%7D%3D%5Ccfrac%7B%5Cpi%20%7D%7B3%7D%5Cstackrel%7Bproduct~rule%7D%7B%20%5Cleft%5B%20%5Cunderset%7Bchain~rule%7D%7B2r%5Ccdot%20%5Ccfrac%7Bdr%7D%7Bdt%7D%7D%5Ccdot%20h%2Br%5E2%5Ccdot%20%5Ccfrac%7Bdh%7D%7Bdt%7D%20%5Cright%5D%7D%20%5C%5C%5C%5C%5C%5C%20-1346%3D%5Ccfrac%7B%5Cpi%20%7D%7B3%7D%5Cleft%5B2%5Csqrt%7B%5Ccfrac%7B307%7D%7B3%5Cpi%20%7D%7D%28-10%29%289%29~~%2B%20~~%20%5Ccfrac%7B307%7D%7B3%5Cpi%20%7D%20%5Ccdot%20%5Ccfrac%7Bdh%7D%7Bdt%7D%5Cright%5D)
![-\cfrac{4038}{\pi }=-\cfrac{180\sqrt{307}}{\sqrt{3\pi }}+\cfrac{307}{3\pi } \cdot \cfrac{dh}{dt}\implies \left[ -\cfrac{4038}{\pi }+\cfrac{180\sqrt{307}}{\sqrt{3\pi }} \right]\cfrac{3\pi }{307}=\cfrac{dh}{dt} \\\\\\ -\cfrac{12114}{307}+\cfrac{180\sqrt{3\pi }}{\sqrt{307}}=\cfrac{dh}{dt}\implies -7.920939735970634 \approx \cfrac{dh}{dt}](https://tex.z-dn.net/?f=-%5Ccfrac%7B4038%7D%7B%5Cpi%20%7D%3D-%5Ccfrac%7B180%5Csqrt%7B307%7D%7D%7B%5Csqrt%7B3%5Cpi%20%7D%7D%2B%5Ccfrac%7B307%7D%7B3%5Cpi%20%7D%20%5Ccdot%20%5Ccfrac%7Bdh%7D%7Bdt%7D%5Cimplies%20%5Cleft%5B%20-%5Ccfrac%7B4038%7D%7B%5Cpi%20%7D%2B%5Ccfrac%7B180%5Csqrt%7B307%7D%7D%7B%5Csqrt%7B3%5Cpi%20%7D%7D%20%5Cright%5D%5Ccfrac%7B3%5Cpi%20%7D%7B307%7D%3D%5Ccfrac%7Bdh%7D%7Bdt%7D%20%5C%5C%5C%5C%5C%5C%20-%5Ccfrac%7B12114%7D%7B307%7D%2B%5Ccfrac%7B180%5Csqrt%7B3%5Cpi%20%7D%7D%7B%5Csqrt%7B307%7D%7D%3D%5Ccfrac%7Bdh%7D%7Bdt%7D%5Cimplies%20-7.920939735970634%20%5Capprox%20%5Ccfrac%7Bdh%7D%7Bdt%7D)
No they don't lie on the same line because all coordinate points would be at different distances from the origin. The only way a point could be at the same line as the others would be they would have to have the same x- or y- axis points. (For example: 6,5; 3,5; and 2,5 would all be on the same line, horizontally, because the 5 in all three coordinates refers to the y- axis aka the horizontal axis
Answer:
764 US Fluid Ounce
Step-by-step explanation:
Refrence Sheet Used: https://media.studyisland.com/pics/FL8thgradereferencesheet.html
27 US Liquid Quarts = 864 US Fluid Ounces, - 100 US Fluid Ounces = 764
B is correct ..............
