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3 years ago

Deon had $25. Then he spent $15 on lunch. What percentage of his money did Deon spend on lunch?

Mathematics

1 answer:

statuscvo [17]3 years ago

5 0

Answer:

Deon spent 60% of his money on lunch.

Step-by-step explanation:

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2 years ago

How do you solve 12x+4y=40?

sergejj [24]

Answer:

12x+4y=40

-4 -4

---------------

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3 years ago

The measurenicnt of the circumference of a circle is found to be 56 centimeters. The possible error in measuring the circumferen

BartSMP [9]

Answer:

(a) Approximate the percent error in computing the area of the circle: 4.5%

(b) Estimate the maximum allowable percent error in measuring the circumference if the error in computing the area cannot exceed 3%: 0.6 cm

Step-by-step explanation:

(a)

First we need to calculate the radius from the circumference:

$c=2\pi r\\r=\frac{c}{2\pi } \\c=8.9 cm$

I leave only one decimal as we need to keep significative figures

Now we proceed to calculate the error for the radius:

$\Delta r=\frac{dt}{dc} \Delta c\\\\\frac{dt}{dc} = \frac{1}{2 \pi } \\\\\Delta r=\frac{1}{2 \pi } (1.2)\\\\\Delta r= 0.2 cm$

$r = 8.9 \pm 0.2 cm$

Again only one decimal because the significative figures

Now that we have the radius, we can calculate the area and the error:

$A=\pi r^{2}\\A=249 cm^{2}$

Then we calculate the error:

$\Delta A= (\frac{dA}{dr} ) \Delta r\\\\\Delta A= 2\pi r \Delta r\\\\\Delta A= 11.2 cm^{2}$

$A=249 \pm 11.2 cm^{2}$

Now we proceed to calculate the percent error:

$\%e =\frac{\Delta A}{A} *100\\\\\%e =\frac{11.2}{249} *100\\\\\%e =4.5\%$

(b)

With the previous values and equations, now we set our error in 3%, so we just go back changing the values:

$\%e =\frac{\Delta A}{A} *100\\\\3\%=\frac{\Delta A}{249} *100\\\\\Delta A =7.5 cm^{2}$

Now we calculate the error for the radius:

$\Delta r= \frac{\Delta A}{2 \pi r}\\\\\Delta r= \frac{7.5}{2 \pi 8.9}\\\\\Delta r= 0.1 cm$

Now we proceed with the error for the circumference:

$\Delta c= \frac{\Delta r}{\frac{1}{2\pi }} = 2\pi \Delta r\\\\\Delta c= 2\pi 0.1\\\\\Delta c= 0.6 cm$

5 0

3 years ago

in a round robin tennis tournament involving 7 players, each player will play every other player twice. How many total matches w

baherus [9]

Total number of ways to make a pair:

The first player can be any one of 7 . For each of those . . .
The opponent can be any one of the remaining 6 .

Total ways to make a pair = 7 x 6 = 42 ways .

BUT ... every pair can be made in two ways ... A vs B or B vs A .
So 42 'ways' make only (42/2) = 21 different pairs.

If every pair plays 2 matches, then (21 x 2) = 42 total matches will be played.

Now, is that an elegant solution or what !

8 0

3 years ago

I need help with this question

k0ka [10]

F(x) = 1 / (x - 2)...when x = 4
f(4) = 1 / (4 - 2)
f(4) = 1/2 <==

f(x) = 1 / (x - 2)...when f(x) = 1
1 = 1 / (x - 2) ...multiply both sides by (x - 2) eliminating it on the right
1(x - 2) = 1
x - 2 = 1
x = 1 + 2
x = 3 <==

8 0

3 years ago

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Deon had $25. Then he spent $15 on lunch. What percentage of his money did Deon spend on lunch?​

Deon had $25. Then he spent $15 on lunch. What percentage of his money did Deon spend on lunch?