Answer:
4
Step-by-step explanation:
This situation has two unknowns - the total number of half dollars and the total number of quarters. Because we have two unknowns, we will write a system of equations with two equations using the two unknowns.
- h+q=31 is an equation representing the total number of coins
- 0.50h+0.25q=11 is an equation representing the total value in money based on the number of coin. 0.50 and 0.25 come from the value of a half dollar and quarter individually.
We write the first equation in terms of q by subtracting it across the equal sign to get h=31-q. We now substitute this for h in the second equation.
0.50(31-q)+0.25q=11
15.5-0.50q+0.25q=11
15.5-0.25q=11
After simplifying, we subtract 15.5 across and divide by the coefficient of q.
-0.25q=-4.5
q=4
We now know of the 31 coins that 4 are quarters.
Answer:
1430
Step-by-step explanation:
Given that a standard deck of cards is 52 cards, we have 13 Diamonds and we need 4 diamonds.
Hence, we have 13C4.
Also, we have 4 kings in a standard deck of cards, and in which we have 2 black kings but we need 1 king.
Hence we have a 2C1
Therefore:
13C4 * 2C1
=> 13! ÷ [4! (13 - 4)!] * 2! ÷ [1! (2-1)!]
=> 13! ÷ [4! (9)!]
=> (1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 x 10 x 11 x 12 x 13) ÷ [(1 x 2 x 3 x 4) (1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9)]
=> (10 x 11 x 12 x 13) ÷ 24
=> (17160 ÷ 24) * (24 ÷ 6)
=> 715
2! ÷ [1! (2-1)!]
=> 2
Hence, we have 715 * 2
=> 1430
Hence, in this case, the correct answer to the question is 1430
Answer:
x=amount invested at 7%
2x=amount invested at 8%
3x=amount invested at 9%
interest=principal*rate*time (time=1 year)
$150=0.07x+0.08*2x+0.09*3x
$150=0.07x+0.16x+0.27x
$150=0.50x
$1500=5x
x=$300 invested at 7%
2x=$600 invested at 8%
3x=$900 invested at 9%
Step-by-step explanation:
Ok I will show my work in the comments
Since you did not attach any picture we cannot say for sure what is the correct answer, but we can discuss the options in order to find the most probable correct answer.
First of all, according to the Cavalieri's principle, an oblique cylinder has the same volume as a right cylinder with the same base surface area and same height.
A cross-section of an oblique cylinder will be a small right cylinder with the same base surface area and a height as small as possible.
I guess the oblique cylinder has height h and it is divided into many (probably 10) cross-sections.
Option A: <span>πr2h
This is exactly the volume of the right cylinder, therefore, unless you are given a cross-section of height h (which would be too easy), this won't be the correct answer.
Option B: </span><span>4πr2h
This is 4 times the right cylinder. Again, here the height of the cross-section should</span> be 4h, but it doesn't sound like a possible data (too easy again).
Option C: <span>1 10 πr2h
Here comes a n issue with the notation: I think the right number you meant to write is (1/10)</span>·πr2h and not 110·<span>πr2h.
If I am right, this means that your oblique cylinder of height h is divided into 10 cross-sections, and therefore the volume of each of these cross-sections will be a tenth of the volume of the oblique cylinder, which means </span>1/10·<span>πr2h.
Option D: </span><span>1 2 πr2h
Here, we have the same notation issue as before. I think you meant (1/2)</span>·<span>πr2h.
Here, your oblique cylinder height h should be divided into only 2 cross-sections. Now, we said the cross-section's height should be the smallest as possible, so an oblique cylinder divided only into two pieces doesn't sound good.
Therefore, the most probable correct answer will be C) </span>(1/10)·<span>πr2h</span>
