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3 years ago

Andy has 31 coins made up of quarters and half dollars, and their total value is $11.00. How many quarters does he have?

Mathematics

1 answer:

charle [14.2K]3 years ago

3 0

Answer:

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.

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2 years ago

Find the integral, using techniques from this or the previous chapter.<br> ∫x(8-x)3/2 dx

Soloha48 [4]

Answer:

$\int x(8-x)^{3/2}dx= -\frac{16}{5} (8-x)^{\frac{5}{2}} +\frac{2}{7} (8-x)^{\frac{7}{2}} +C$

Step-by-step explanation:

For this case we need to find the following integral:

$\int x(8-x)^{3/2}dx$

And for this case we can use the substitution $u = 8-x$ from here we see that $du = -dx$ , and if we solve for x we got $x = 8-u$ , so then we can rewrite the integral like this:

$\int x(8-x)^{3/2}dx= \int (8-u) u^{3/2} (-du)$

And if we distribute the exponents we have this:

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Now we can do the integrals one by one:

$\int x(8-x)^{3/2}dx= -8 \frac{u^{5/2}}{\frac{5}{2}} + \frac{u^{7/2}}{\frac{7}{2}} +C$

And reordering the terms we have"

$\int x(8-x)^{3/2}dx= -\frac{16}{5} u^{\frac{5}{2}} +\frac{2}{7} u^{\frac{7}{2}} +C$

And rewriting in terms of x we got:

$\int x(8-x)^{3/2}dx= -\frac{16}{5} (8-x)^{\frac{5}{2}} +\frac{2}{7} (8-x)^{\frac{7}{2}} +C$

And that would be our final answer.

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2 years ago

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2 years ago

Read 2 more answers

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The linear regression equation that represents this data is given as follows: y = 22x - 518.

Using this equation, when 38 passes are thrown, the expected yardage is of 318 yards.

<h3>How to find the equation of linear regression?</h3>

To find the regression equation, also called line of best fit or least squares regression equation, we need to insert the points (x,y) in the calculator. These points are given on a table or in a scatter plot in the problem.

In the context of this problem, the input and output are given as follows:

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Output: number of passing yards obtaining by Mahomes/KC.

The points to be inserted in the calculator are given as follows:

(39, 360), (35, 235), (35, 262), (37, 249), (40, 338).

Hence the equation is given by:

y = 22x - 518.

With 38 passes, the expected yardage is calculated as follows:

y = 22(38) - 518 = 318 yards.

More can be learned about linear regression at brainly.com/question/22992800

#SPJ1

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10 months ago

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2 years ago