The time in minutes for each of Sam's phone calls this week are shown in the list

One positive number is 14 less than another positive number. If the reciprocal of the smaller number is added to five times the

Kipish [7]

Let's call the two numbers $s$ and $l$ .

Given these variables, we can say: $s = l - 14$ , based on the first sentence in the problem.

Also, remember that the reciprocal of a number is simply 1 divided by the number. Thus, we can say that:

$\dfrac{1}{s} + 5\Big( \dfrac{1}{l} \Big) = \dfrac{1}{4}$

To solve, we can simply substitute $l -14$ in for $s$ in the second equation and solve.

$\dfrac{1}{l - 14} + \dfrac{5}{l} = \dfrac{1}{4}$

Set up

$\dfrac{l}{l(l - 14)} + \dfrac{5(l - 14)}{l(l - 14)} = \dfrac{1}{4}$

Get terms on the left side to a common denominator for easier addition

$\dfrac{l + 5l - 70}{l(l - 14)} = \dfrac{1}{4}$

Simplify

$4(6l - 70) = l(l - 14)$

Cross multiplication ( $\frac{a}{b} = \frac{c}{d} \Rightarrow ad = bc$ )

$24l - 280 = l^2 - 14l$

Simplify

$l^2 - 38l + 280 = 0$

Subtract $24l - 280$ from both sides of the equation

$(l - 10)(l - 28) = 0$

Factor left side of the equation

$l = 10, 28$

Zero Product Property

Now, notice that we have found two solutions, but the problem is only asking for one. This likely means that one of our solutions is extraneous. Let's take a look. Remember that the smaller positive number is equal to 14 less than the larger number. However,

$s = 10 - 14 = -4$ ,

Since $s$ is not positive in this case, $l = 10$ is not a solution.

Thus, $l = 28$ is our only solution. In this case,

$s = 28 - 14 = 14$ ,

which means that the smaller number is 14 and the larger number is 28.

5 0

3 years ago

a paper airplane can be made out of two different pieces of paper: a circular piece 10 inches wide and a square piece 11 inches

madreJ [45]

Compare the areas of the 2 different pieces of paper.

For the circle, the area is A=pi * r^2, which works out to A = pi(5 inches)^2.

For the square, the area is A = s^2, where is the side length, which here is 11 inches.

Finish these calculations, and then compare your two areas. Which is the larger?

5 0

3 years ago

The figure below shows the front side of a purse in the shape of a trapezoid. Find the area of the trapezoid.

loris [4]

Answer:

110 in²

Step-by-step explanation:

Area of trapezoid formula:

A = (b₁ + b₂)h/2

Substitute the values on the sketch and find the area:

A = (9 + 13)*10/2 = 110 in²

8 0

2 years ago

Answer the question If you're right I'll MARK YOU BRAINLIEST!!

natka813 [3]

Answer:

$2x\sqrt{40x}-2x\sqrt{5}$

Step-by-step explanation:

$2x\sqrt{40x}-2x\sqrt{5}$ is found by first, siplifying the radicals in the parenthesis. $\sqrt{8x^{2} }$ can be simplified as $2x\sqrt{2}$ and $-2\sqrt{x}$ stays the same. Now we have to multiply these two by $\sqrt{5x}$ which then results in $2x\sqrt{40x}-2x\sqrt{5}$

4 0

3 years ago

Total mass vs. numbers of cd and numbers of cd

Gekata [30.6K]

Answer: Choice A) M = 0.25n + 100

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Explanation:

For now, I'll treat n as x, and M as y.

In other words,

x = number of CDs
y = total mass in kg

Let's select two points from this graph. I'll pick (200,150) and (400,200)

The slope of the line through those points is

m = (y2-y1)/(x2-x1)

m = (200-150)/(400-200)

m = 50/200

m = 0.25

Now we'll use the point (x,y) = (200,150) along with that slope value to find the y intercept b

y = mx+b

150 = 0.25*200+b

150 = 50+b

150-50 = b

100 = b

b = 100

You could also use (x,y) = (400,200) and you should get the same b value.

In fact, any other point from this graph works as well.

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Since m = 0.25 and b = 100, we go from y = mx+b to y = 0.25x+100

This then translates over to M = 0.25n + 100 which is choice A

To help verify this, let's say we plugged in n = 100

M = 0.25*n + 100

M = 0.25*100 + 100

M = 25 + 100

M = 125

Which is confirmed by what the graph shows. I'll let you check the other points as well.

7 0

3 years ago